JPH08256905A - Rice cooker - Google Patents

Abstract

PURPOSE: To improve heat efficiency in heating for rice cooking by arranging a reflector made of material with high heat conductivity at the lower part of an outer oven and also on the lower side of a heater and providing a projecting part formed so as to come in contact with the reflector extending over nearly the entire circumference on the outer peripheral part of an inner oven. CONSTITUTION: The frame 1 of this rice cooker comprises the outer oven 2, an outer cylinder 3 incorporating the outer oven 2, and a bottom plate 4, etc., and the inner oven 11 which forms a nearly cylindrical shape cylindrical projecting part 13 extending downward from the boundary part of a side face part 11a and a curved surface part 11c is housed in the outer oven 2. The reflector 21 provided with the heat conductivity is assembled with the outer oven 2 along its lower face, and a reverse tapered part 22 confronting with the curved surface part 11c is provided in the outer peripheral part of the reflector 21, a horizontal flange part 23 provided on the outer peripheral part of the reverse tapered part 22 is supported on the step part 8 of the outer oven 2. Also, glass 31A, 31B on which an electric sheath heater 34 which heats the inner oven 11 is mounted are fixed on the inner bottom of the outer oven 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice cooker, and more particularly, to a heating structure of an inner pot for containing cooked food.

[0002]

2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Patent Publication No. 61-47525, the outer pot is made of aluminum having high heat conductivity and is also used as a reflector, and the side faces of the outer pot and the inner pot. Keep the distance between the parts small and when cooking rice,
There has been proposed a rice cooker that gives the inner pot the heat of the outer pot heated by the heating of a heater provided between the outer pot and the inner pot. This rice cooker is intended to prevent uneven cooking.

However, in this rice cooker, the outer pot itself becomes hot due to the heating of the heater, so that heat easily escapes to the outside, and there is a problem that the heat efficiency is deteriorated due to the loss of the heat.

Further, in order to improve heating efficiency and uniform heating, a flange-shaped protrusion is formed in the middle of the outer surface of the side portion of the inner pot, and a heating space is provided below the protrusion between the inner pot and the outer pot. Can be formed. As a result, it is possible to prevent the temperature from rising to a high temperature, which is not so important in cooking rice, and to efficiently and uniformly heat the lower side of the inner pot, which is important for cooking rice.

However, even with this rice cooker, there are still points to be improved. First of all, since the protrusions are projected almost horizontally from the outer surface of the side portion of the inner pot, the diameter of the outer pot becomes large and the entire rice cooker also becomes large. Further, since the heating space is formed between the inner pot and the outer pot, and the heating space is limited only to the lower portions of the inner pot and the outer pot, the outer pot becomes hot, and therefore the outer pot is heated. A heat shield plate or heat insulating material is required on the outer surface of the, thus increasing the cost.

[0006]

As described above, in the conventional rice cooker as described in Japanese Patent Publication No. 61-47525, the outer pot is made of aluminum and also serves as a reflector in order to prevent uneven cooking. Therefore, there was a problem that heat could easily escape to the outside. Further, even in a rice cooker in which a flange-shaped protrusion is formed in the middle of the outer side surface of the inner pot and a heating space is formed between the inner pot and the outer pot below the protrusion, more uniform and efficient heating is achieved. Although there is an advantage that it can be done, the flange-shaped protrusions are formed on the outer surface of the side of the inner pot, resulting in an increase in size and the need for a heat insulating material when the outer pot becomes hot, which leads to an increase in cost. Therefore, further improvement is desired.

The present invention is intended to solve such problems, and can improve the heat efficiency in the heating for cooking rice so that the rice can be cooked deliciously, and the shape can be reduced, and the manufacturing process can be improved. It is an object to provide a rice cooker that can reduce costs.

[0008]

In order to achieve the above object, the present invention provides an inner pot for accommodating cooked food, an outer pot for accommodating the inner pot, and a space between these inner and outer pots. In a rice cooker equipped with a heater arranged below the
A reflecting plate made of a material having good thermal conductivity is provided under the outer pot and below the heater, and a projection formed so as to come into contact with the reflecting plate is provided around the entire outer peripheral portion of the inner pot. It has been extended downward.

[0009]

In the rice cooker of the present invention, when cooking rice, the inner pot containing the food to be cooked is contained in the outer pot, and the heater between the inner pot and the outer pot heats the inner pot. At this time, the radiant heat from the heater is reflected to the inner pot side by the reflector plate provided under the outer pot and below the heater, but the protrusion extending downward from the outer peripheral part of the inner pot serves as the reflector plate. Because of the contact, the radiant heat from the heater is prevented from leaking to the outside, and the heat received by the reflector from the heater is directly transferred to the inner pot by heat conduction. Thus, in the inner pot, the lower part, which is particularly important for cooking rice, is efficiently and uniformly heated. Further, a large amount of heat can be stored in the vicinity of the protrusion of the inner pot, and this heat storage enables efficient steaming and heat retention after cooking rice.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the rice cooker of the present invention will be described below with reference to the drawings. Reference numeral 1 is a bowl of a rice cooker, and the bowl frame 1 is composed of an outer pot 2 made of metal or the like, an outer cylinder 3 made of synthetic resin or the like having the outer pot 2 built therein, a bottom plate 4 and the like. The bottom plate 4 is an outer cylinder 3
It is fixed by covering the lower surface opening. Also, this outer cylinder 3
An inward flange 5 is formed around the upper end of the. On the other hand, the outer pot 2 has a cylindrical shape with a bottom, and a flange portion 6 formed on the peripheral portion of the upper end is fixed to the inward flange portion 5 of the outer barrel 3 with a screw 7. Further, a horizontal step portion 8 that faces upward inside the outer pot 2 is formed on the lower portion of the side surface of the outer pot 2 over the entire circumference. Further, a bulging portion 9 is formed so as to bulge upward in the central portion of the lower surface of the outer pot 2, and an opening portion 10 is formed in the central portion of the bulging portion 9.

Reference numeral 11 denotes an inner pot. The inner pot 11 accommodates rice to be cooked, such as rice and water, and is housed in the outer pot 2 so as to be insertable and removable from above. And the inner pot
11 is formed in a container shape with an upper surface opened by aluminum die casting or the like. More specifically,
The inner pot 11 has a substantially cylindrical side surface portion 11a whose axial direction is a vertical direction, a horizontal bottom surface portion 11b, and a substantially spherical curved surface portion between the side surface portions 11a and 11b that is smoothly continuous with these. 11c and. A substantially horizontal flange portion 12 is formed outward at the upper end of the inner hook 11. Further, the inner hook 11 is integrally formed with a substantially cylindrical tubular projection 13 extending downward from a boundary portion between the side surface portion 11a and the curved surface portion 11c on the outer peripheral portion thereof. A heating space 14 is formed between the cylindrical protrusion 13, the curved surface portion 11c and the bottom surface portion 11b of the lower portion of the inner pot 11, and the reflection plate 21 described later. Also, the inner pot 11
An annular protrusion 15 is formed at the center of the outer surface of the bottom surface portion 11b. The thickness of the side surface portion 11a of the inner pot 11 gradually increases from the upper end thereof toward the boundary with the lower cylindrical protrusion 13, and the thickness of the cylindrical protrusion 13 increases from the lower end thereof. The thickness gradually increases toward the boundary with the upper side surface portion 11a. further,
A small gap 16 is formed between the inner surface of the outer hook 2 and the outer surface of the inner hook 11 housed in the outer hook 2.

Further, a reflecting plate 21 made of a material having a high thermal conductivity such as aluminum is assembled inside the outer pot 2 along the lower surface thereof. The reflecting plate 21 has a reverse taper portion 22 on the outer peripheral portion facing the curved surface portion 11c of the inner pot 11. Further, on the outer peripheral portion of the reverse taper portion 22, a horizontal flange portion over the entire circumference thereof is provided. Has 23. The flange portion 23 is placed on the stepped portion 8 of the outer pot 2 to support the reflection plate 21, and the other portion of the reflection plate 21 is not in contact with the outer pot 2. Also, in the center of the reflector 21,
A bulging portion 24 that covers the bulging portion 9 of the outer pot 2 is formed, and an opening portion 25 is formed in the center of the bulging portion 24. Although the upper portion of the bulging portion 24 is located inside the annular protrusion 15 of the inner hook 11, it does not contact the inner hook 11.

On the inner bottom surface of the outer pot 2, a pair of left and right insulators 31A and 31B are fixed by screws 32. These insulators 31A and 31B are the openings 33 formed in the reflection plate 21.
Pierces through and projects above. And both insulators
An electric heating type sheath heater 34 for heating the inner pot 11 is mounted on 31A and 31B. This heater 34 is an insulator
Heater fixing plate 36 fixed by screws 35 on 31A and 31B
It is fixed by A and 36B. The heater 34 is one, and is bent and doubled as shown in FIG.
Except for the terminal portions 37 at both ends, it is positioned horizontally between the reflection plate 21 and the inner pot 11. Then, the outer peripheral portion 34a of the heater 34 is
It faces the reverse taper portion 22 of the reflection plate 21, and the inner peripheral portion 34b of the heater 34 faces the tapered outer peripheral surface of the bulging portion 24 of the reflection plate 21.

Further, a screw 41 is provided on the lower side of the bulging portion 9 of the outer pot 2.
A heat sensitive sensor 43 for detecting the temperature of the inner pot 11 is supported on the back plate 42 fixed by the above so as to be vertically movable. The thermal sensor 43 is biased upward, penetrates the openings 10 and 25 of the outer pot 2 and the reflection plate 21 and projects upward, and is elastically attached to the bottom portion 11b of the inner pot 11. It comes into contact with.

Reference numeral 51 is a lid, and the lid 51 is provided on the upper side of the device frame 1 so as to be rotatable and openable. And the lid 51
Has an annular back plate 53 made of synthetic resin or the like fixed to the lower peripheral portion of the outer lid 52 made of synthetic resin or the like, and an inner lid 54 made of aluminum or the like fixed to the inside of the back plate 53. There is. The inner lid 54 closes the upper surface opening of the inner pot 11. A packing 55 is provided between the back plate 53 and the inner lid 54 so as to be in close contact with the flange portion 12 of the inner pot 11 over the entire circumference. ing.

Next, the operation of the above configuration will be described. At the time of use, first, the inner pot 11 containing rice to be cooked, water, etc. is housed in the outer pot 2 and the lid 51 is closed.
In this state, the bottom surface portion 11b of the inner pot 11 contacts the temperature sensor 43, and the lower end of the cylindrical protrusion 13 of the inner pot 11 is set to the reflection plate 21.
It contacts on the flange portion 23 of the whole circumference. Thus, the cylindrical protrusion 13 of the inner hook 11 and the curved surface portion 11c and the bottom surface portion 11
A heating space 14 including a heater 34 is formed between b and the reflection plate 21. In addition, the inner pot located above the outer pot 2
The packing 55 of the lid 51 is in close contact with the flange portion 12 of 11.

When rice is cooked, the heater 34 is used for the inner pot.
11 is heated. At this time, the temperature of the inner pot 11 is detected by the heat-sensitive sensor 43 which is in contact with the bottom portion 11b of the inner pot 11,
On the basis of this, the on / off of the heater 34 is controlled, and a predetermined rice cooking process is performed.

When the inner pot 11 is heated, the radiation from the heater 34 is reflected to the inner pot 11 side by the reflecting plate 21 made of aluminum. Moreover, the lower end of the cylindrical projection 13 of the inner pot 11 made of aluminum is in contact with the flange portion 23 on the outer periphery of the reflection plate 21 over the entire circumference, and the heater 34 is completely enclosed in the heating space 14. Therefore, the radiant heat from the heater 34 is unlikely to leak outside. As a result, the radiant heat from the heater 34
It is efficiently supplied especially to the lower part of 11, and the thermal efficiency in heating for cooking rice is improved. With this,
The heat received by the reflector 21 from the heater 34 is generated by the reflector 21 and the inner pot 11
It is directly transferred to the inner pot 11 by heat conduction through the contact portion with. The contact portion of the inner pot 11 with the reflection plate 21 is a cylindrical protrusion 13
Therefore, sufficient heat is also supplied to the curved surface portion 11c from the lower side of the side surface portion 11a of the inner pot 11 which is located relatively far from the heater 34. Thus, in the inner pot 11, the lower part, which is particularly important for cooking rice, is efficiently and uniformly heated over a wide range. Therefore, the rice can be cooked quickly and deliciously.

Furthermore, since the high temperature is maintained by the heat accumulated in the cylindrical protrusion 13 and the heating space 14 when the heater 34 is heated, this heat accumulation does not particularly energize the heater 34, and thus the rice Good steaming to remove excess water. In addition, the heat storage is effective for keeping heat after steaming. Moreover, since the thickness of the side surface portion 11a of the inner hook 11 is gradually increased from the upper end thereof toward the cylindrical projection portion 13, the thickness of the cylindrical projection portion 13 is also gradually increased toward the side surface portion 11a. Since the heat capacity near the boundary between the side surface portion 11a and the cylindrical protrusion 13 is large and a large amount of heat can be stored in this vicinity, the above-mentioned thermal characteristics after cooking rice can be further improved. That is, after the rice is cooked, the rice is cooled from the upper side, while the heat is accumulated near the boundary between the side surface portion 11a and the cylindrical protrusion 13 to keep the upper side of the rice at a high temperature and efficiently retain the heat. be able to.

Further, according to the construction of the above-mentioned embodiment, since the cylindrical projection 13 has a shape in which the side surface portion 11a of the outer peripheral portion of the inner hook 11 is extended downward as it is, a flange-shaped projection portion is almost formed on the outer surface. Unlike the case where the horizontally placed inner pot is housed in the outer pot, the inner pot 11
The diameter of the outer pot 2 for accommodating the inner pot 11 can be reduced without reducing the inner volume of the inner pot 11. Therefore, it is not necessary to increase the size of the device frame 1 that forms the outer shell of the entire rice cooker. Further, even when the inner pot 11 is made by aluminum die casting, the tubular protrusion 13 having the above-described shape does not make it difficult to form the flange portion 12 at the upper end of the inner pot 11. The flange portion 12 is convenient as a handle portion when the user holds the inner hook 11.

Further, in this embodiment, the outer pot 2 which is not involved in heating does not need to be made of expensive aluminum, and is a smaller reflection plate located only in the lower portion of the outer pot 2.
Since only 21 needs to be made of aluminum, the manufacturing cost can be reduced. At the same time, because the structure is such that heat does not easily escape from the side surface to the outside, it is not necessary to provide a heat shield plate or a heat insulating material on the outer surface of the outer pot 2, thus further reducing the cost.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made. For example,
Although one heater is used in the above embodiment, a plurality of heaters may be provided. Further, it is possible to provide a plurality of heaters with different diameters and heights.

Further, in the above embodiment, the outer pot 2 and the reflector 21 are arranged.
However, as in the second embodiment shown in FIG. 3, the reflector 21 is integrally formed on the bottom of the outer pot 2 made of a material having good thermal conductivity such as aluminum. Outer pot 2
A heat shield plate 61 may be provided below the reflection plate 21.

Further, in the above-described embodiment, the cylindrical protrusion 13 of the inner hook 11 extends below the bottom surface portion 11b, but as in the third embodiment shown in FIG. 13 may be extended only above the bottom surface portion 11b.

[0025]

According to the present invention, a projection formed by disposing a reflection plate made of a material having good heat conductivity below the outer pot and below the heater and contacting the reflection plate. Since it has been extended downwards over the entire circumference of the inner pot,
Radiant heat from the heater can be supplied to the lower part of the inner pot without escaping to the outside, and since heat is transmitted directly from the reflector to the inner pot, the lower part, which is particularly important for cooking rice, is heated uniformly and efficiently in the inner pot. You can cook rice deliciously. At the same time, a large amount of heat can be stored in the vicinity of the protrusion of the inner pot, so that steaming and heat retention after cooking rice can be efficiently performed. Further, since the protrusion extends downward from the outer peripheral portion of the inner pot, it is not necessary to enlarge the outer pot for accommodating the inner pot, and the entire rice cooker can be downsized. Furthermore, since it is difficult for heat to escape to the outside, there is no need for heat shields or heat insulating materials, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a rice cooker of the present invention, (a) is an overall cross-sectional view, and (b) is an enlarged view of the vicinity of the tip of a cylindrical protrusion.

FIG. 2 is a plan view of the same.

FIG. 3 is a cross-sectional view showing a second embodiment of the rice cooker of the present invention in the vicinity of a cylindrical protrusion.

FIG. 4 is a cross-sectional view of the vicinity of a cylindrical protrusion showing a third embodiment of the rice cooker of the present invention.

[Explanation of symbols]

 2 Outer pot 11 Inner pot 13 Cylindrical protrusion (projection) 21 Reflector 34 Heater

Claims (1)

[Claims] 1. An inner pot for accommodating cooked food, an outer pot for accommodating the inner pot, and a heater arranged below the inner pot and the outer pot for heating the inner pot. In the rice cooker, a reflecting plate made of a material having good thermal conductivity is arranged under the outer pot and under the heater, and a protrusion formed so as to come into contact with the reflecting plate is provided on an outer peripheral portion of the inner pot. The rice cooker is characterized in that it extends downward over almost the entire circumference.