JPH07275115A - Electric rice cooker - Google Patents

Abstract

PURPOSE:To provide an electric rice cooker of electromagnetic induction heating type capable of performing ideal heating control by detecting the inside temperature of an inner pot with high accuracy. CONSTITUTION:This electric rice cooker which performs the heat cooking of food to be cooked in the inner pot 3 by applying electromagnetic induction heating to the inner pot made of magnetic material is equipped with the inner pot 3 comprised of the synthetic structure of an outside member 3a and an inside member 3b and in which the food to be cooked is housed, a bottom pan 23 which houses the inner pot 3 loadably/unloadably, an induction coil 26 arranged at the lower side of the bottom pan 23 and which applies the electromagnetic induction heating to the inner pot 3, and a thermosensible element arranged at a position to be brought into contact with a part of the bottom of the inner pot 3 and which detects the inside temperature of the inner pot 3. A part to be brought into contact with the thermosensible element 28 on the bottom of the inner pot is comprised so as to expose the inside member 3b by cutting the outside member 3a.

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 and cooking an object to be cooked in an inner pot by electromagnetically heating an inner pot made of a magnetic material.

[0002]

2. Description of the Related Art Generally, an electromagnetic induction heating type electric rice cooker is
As shown in FIG. 5, a lid body 1 and a main body 2 are provided, and the lid body 1 has a lid cover 12 on the back side of the outer lid 11.
An inner lid 13 for opening and closing the opening of the main body 2 and a packing 14 for sealing vapor are attached to the unit 2. The lid 1 is rotatably attached to the main body 2 by a hinge portion 15 and detachably engaged with the main body 2 by an engaging portion 16.

The main body 2 is a bottomed cylindrical container having an open top surface, and is provided with an outer case 21, a side case 22, a bottom pot 23 and an upper ring 24, and an inner pot 3 made of a magnetic material inside the side case 22. Is designed to be detachably inserted.

An induction heating coil 26 is arranged between the lower surface of the bottom pot 23 and the base 25, and the induction heating coil 26 and the base 25 improve efficiency and leakage of magnetic flux. Ferrite 27 is arranged for prevention.
Further, a heat sensitive element 28 for detecting the temperature of the inner pot 3 is provided at the center of the bottom pot 23.

A circuit board 29, on which a control circuit for supplying a high-frequency current to the induction heating coil 26 to generate magnetic lines of force is mounted, is installed below the base 25, and the components of the circuit board 29 are further installed. A cooling fan motor 31 having a cooling fan 30 for cooling is installed. Further, inside the main body 2, a power cord reel 33 for winding and storing the power cord 32 is provided.

In this structure, when an object to be cooked such as rice is put in the inner pot 3 and heated, the control circuit supplies a high frequency current to the induction heating coil 26, and the induction heating coil 26 generates magnetic lines of force. The inner pan 3 is heated by electromagnetic induction by the lines of magnetic force, and the food to be cooked is heated. The heat-sensitive element 28 indicates that the water content of the food to be cooked has evaporated and disappeared due to heating, and the bottom temperature of the inner pot 3 has risen sharply to 100 ° C. or more.
Is detected, the control circuit determines that the cooking has ended, and stops the supply of the high frequency current to the induction heating coil 26. In this way, the electric rice cooker automatically performs the heating of the food to be completed.

By the way, it is often delicious to eat cooked foods such as rice in a warm state. Therefore, in the conventional electric rice cooker, the heat retaining heater 34 is wound around the outer periphery of the side case 22 in order to keep the cooked food warm. The heat-retaining heater 34 is energized after cooking to keep the food to be cooked.

Conventionally, stainless steel was used as the material of the inner pot 3, but the heat insulation is very poor with stainless steel alone because of low thermal conductivity. Therefore, recently, the magnetic material 2 is formed by laminating the stainless material 3a as the outer member and the aluminum material 3b having good thermal conductivity as the inner member.
A plywood with a heavy structure is used as the inner pot 3. With this structure, the heat-sensitive element 28 provided for controlling the cooking rice heating
Is the outer member (stainless steel 3
It comes into contact with a), and heating control is performed while detecting the temperature.

[0009]

In the inner pot 3 having the double structure of the magnetic body described above, the outer circumference is entirely made of the stainless steel material 3a, and the heat sensitive element 28 installed for controlling the rice cooking sequence is made of the stainless steel material. Only 3a can be contacted.
However, since the stainless steel material 3a directly becomes a heating body, the heat effect of self-heating is large and the thermal conductivity is poor, so that there is a difference in temperature between the internal temperature of the inner pot 3 and the stainless steel material 3a on the outer circumference. For this reason, conventionally, since the heating control is performed while correcting the temperature difference, it is far from the ideal heating control.

Therefore, it is an object of the present invention to provide an electromagnetic induction heating type electric rice cooker capable of accurately detecting the internal temperature of an inner pot and controlling ideal heating.

[0011]

An electric rice cooker according to the present invention is composed of a plywood structure of an outer member and an inner member, and an inner pot in which an object to be cooked is stored, and a bottom pot in which the inner pot is detachably stored. And an induction coil arranged under the bottom pan to electromagnetically heat the inner pot, and a heat-sensitive element arranged at a position in contact with a part of the bottom surface of the inner pot to detect the internal temperature of the inner pot. The outer member was cut out at the portion of the bottom surface of the unit that comes into contact with the heat-sensitive element so that the inner member was exposed.

In this case, it is preferable that the outer member of the inner pot is made of stainless steel and the inner member is made of aluminum.

Further, the bottom portion of the inner pot of the inner pot exposed is formed by cutting out the outer member and embedding the inner member in the portion so that the bottom face of the inner pot is flush.

Further, the bottom surface portion of the inner pot of the inner pot exposed is formed by cutting out the outer member so that the inner member projects more than the outer member.

[0015]

In the structure of the present invention, the temperature of the inner member of the magnetic double-layered inner pot is directly detected by the heat-sensitive element, and the inner member is made of an aluminum material having a high thermal conductivity. Can detect the closest temperature,
Highly accurate heating control can be performed.

[0016]

1 is a block diagram showing a first embodiment of an electric rice cooker according to the present invention, in which the same components as those shown in FIG. 5 are designated by the same reference numerals. As shown in the enlarged view of FIG. 2, the electric rice cooker according to the present embodiment is configured such that the stainless steel material 3a near the center of the bottom surface of the inner pot 3 is cut out to expose the inner aluminum material 3b. 3b has a configuration in which the heat sensitive element 28 is arranged so as to be in direct contact with the heat sensitive plate 28a. The other structure is the same as the structure shown in FIG.

According to this structure, the heat-sensitive element 28 is provided in the inner pot 3
The inner material of the inner pot 3 is in contact with the aluminum material 3a, and the aluminum material 3b does not become a heating element like the stainless material 3a. It can be detected by the heat sensitive element 28, and heating control with higher accuracy than in the past can be executed.

FIG. 3 is a constitutional view showing a second embodiment of the electric rice cooker according to the present invention, and is an enlarged view of an essential part showing the vicinity of the center of the bottom surface of the inner pot 3 in an enlarged manner. In the electric rice cooker according to this embodiment, the stainless steel material 3a in the vicinity of the center of the bottom surface of the inner pot 3 is cut out, and the aluminum member 3b which is the inner member is embedded in the cut out portion so that the bottom surface of the inner pot 3 is flush with the surface. The heat sensitive element 28 directly contacts the embedded aluminum material 3b via the heat sensitive plate 28a. The other structure is the same as the structure shown in FIG.

Also in this structure, since the heat-sensitive element 28 is in contact with the aluminum material 3a of the inner pot 3, the temperature closest to the internal temperature of the inner pot 3 can be detected by the heat-sensitive element 28. Higher precision heating control can be performed. Further, according to the configuration of the present embodiment, since the bottom of the inner pot 3 is not formed with a depression, foreign matter such as dust is unlikely to adhere, and the temperature detection accuracy of the thermosensitive element 28 is improved.

FIG. 4 is a constitutional view showing a third embodiment of the electric rice cooker according to the present invention, and is an enlarged view of the principal part showing the substantially central portion of the bottom surface of the inner pot 3 in an enlarged manner. In the electric rice cooker according to the present embodiment, the stainless steel material 3a near the center of the bottom surface of the inner pot 3 is cut out, and the aluminum material 3b as the inner member is squeezed into the cutout portion so as to have a shape protruding from the stainless steel material 3a. The heat sensitive element 28 is configured to directly contact the protruding aluminum material 3b through the heat sensitive plate 28a. The other structure is the same as the structure shown in FIG.

Also in this structure, since the heat-sensitive element 28 is in contact with the aluminum material 3a of the inner pot 3, the temperature closest to the internal temperature of the inner pot 3 can be detected by the heat-sensitive element 28, which is conventionally used. Higher precision heating control can be performed. Further, according to the configuration of this embodiment, the aluminum material 3 is provided below the stainless steel material 3a which is a heating element.
Since the protrusion of b makes it less likely to be affected by external heat, the accuracy of temperature detection by the thermosensitive element 28 is improved.

[0022]

According to the present invention, the inner member having a high thermal conductivity is exposed at the portion of the bottom surface of the inner pot of the magnetic double layer structure that comes into contact with the heat sensitive element. Since the temperature is detected by the heat-sensitive element, the internal temperature of the inner pot can be detected with high accuracy, and heating control can be performed with higher accuracy than in the conventional case, so that delicious rice can be cooked.

Further, if the exposed structure of the inner member is made to project from the outer member, it is less susceptible to the heat of the outer member, so that the internal temperature of the inner pot can be detected more accurately.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of an electric rice cooker according to the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is an enlarged view of a main part showing a second embodiment of the electric rice cooker according to the present invention.

FIG. 4 is an enlarged view of the essential parts showing the third embodiment of the electric rice cooker according to the present invention.

FIG. 5 is a configuration diagram showing an example of a conventional electric rice cooker.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lid body 2 Main body 3 Inner pot 3a Stainless steel material (outer member) 3b Aluminum material (inner member) 11 Outer lid 12 Lid cover 13 Inner lid 14 Packing 15 Hinge portion 16 Engaging portion 21 Outer case 22 Side case 23 Bottom pot 24 Upper ring 25 Base 26 Induction heating coil 27 Ferrite 28 Thermal element 29 Circuit board 30 Cooling fan 31 Cooling fan motor 32 Power cord 33 Power cord reel

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masato Nakatani 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Prefecture Sharp Co., Ltd. Within the corporation

Claims (4)

[Claims] 1. An inner pot having a plywood structure of an outer member and an inner member in which an object to be cooked is stored, a bottom pot for detachably storing the inner pot, and a bottom pot disposed below the bottom pot. The thermosensitive element on the bottom surface of the inner pot is provided with an induction coil for electromagnetically heating the inner pot and a heat-sensitive element arranged at a position in contact with a part of the bottom surface of the inner pot to detect an internal temperature of the inner pot. The electric rice cooker is characterized in that the outer member is cut out so that the inner member is exposed at a portion contacting with the inner member. 2. The electric rice cooker according to claim 1, wherein the outer member of the inner pot is made of a stainless material and the inner member is made of an aluminum material. 3. A bottom surface portion of the inner pot exposed by the inner member is formed by embedding the inner member in a cutout portion of the outer member so that the bottom face of the inner pot is flush with the inner pot. The electric rice cooker according to claim 1. 4. The bottom surface portion of the inner pot exposed by the inner member is formed by cutting out the outer member so that the inner member projects more than the outer member. The electric rice cooker described in 1.