JP2867440B2 - rice cooker - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial application field) The present invention relates to a radiant heating rice cooker.

(Prior Art) Conventionally, in a hot plate type rice cooker in which a container is placed on a plate-shaped heating element, the cooked state of a portion close to the heating element becomes too soft and uneven cooking occurs. This is because the temperature rise at the bottom side of the container is fast and the speed is fast. Further, in the hot plate type rice cooker, if the container is deformed or corroded, the adhesion between the container and the heating element is deteriorated, the heat conduction becomes uneven, and the unevenness in cooking is further deteriorated. Further, in a so-called furnace type rice cooker in which containers are provided at intervals on an annular sheathed heater and cooked by radiant heat, the cooked state becomes too soft at the side of the container close to the heating element, and at the center of the inside of the container. There was a problem of becoming hard. This is because the temperature of the upper part of the container rises quickly and its speed is high. Further, a means for generating heat in the whole container by electromagnetic induction heating is conceivable, but it has a problem that it is expensive and the body becomes heavy.

To solve such a problem, Japanese Patent Application Laid-Open
In Japanese Patent No. 171515, a groove is formed spirally on the upper surface of a heat insulating base material such as a ceramic fiber provided inside the plate as a whole and a heating wire is provided in the groove and a case such as a stainless steel plate is used. There has been proposed a rice cooker in which covered heating elements are provided at intervals below a container and the container is heated mainly by radiating radiant heat from the upper surface of the heating element.

(Problems to be Solved by the Invention) In the above-mentioned conventional technology, since the bottom side of the container is mainly heated by radiant heat from the upper surface of the heating element, the cooked rice is hard on the upper side in the container like the hot plate rice cooker. There is a fear that the situation may occur. In addition, since a low heat dissipation member is provided on the entire lower portion of the heating wire, heat radiation conditions from the surface of the heating element are poor, and the heating wire is likely to be in a very high temperature state. However, it is necessary to reduce the power consumption density of the heating wires in order to secure this life, and thus the heating wires must be made thicker or longer, resulting in poor workability.

Furthermore, in the above-mentioned prior art, since the heat capacity of the heating element itself becomes large, the speed at which heat is generated at the beginning of energization is slowed down, so that the speed up to boiling at the time of cooking rice is reduced, and the rice cooking performance is reduced. Furthermore, since the heat generating element has a large heat capacity, the heat radiation condition is low, so that the high temperature state continues for a relatively long time after cooking rice or the like, which may adversely affect electronic components and the like. In order to prevent this adverse effect, a heat-resistant structure must be provided.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rice cooker that solves the above-mentioned problems, improves the heat radiation condition of the heating element, and can cook rice without uneven cooking.

[Structure of the Invention] (Means for Solving the Problems) The rice cooker according to claim 1 of the present invention has a container main body, a container placed and stored on the upper part of the container main body, and the container main body and the container. The side space and the bottom space for heating formed between the side portions and the bottom portion, a plate-shaped member provided in the bottom space and facing the bottom of the container, and the lower surface side of the plate-shaped member is higher than the upper surface side. A heating section fixedly provided below the plate-shaped member so as to have a high temperature, and a communication space provided on a side portion of the plate-shaped member and communicating in a vertical direction, wherein the plate-shaped member is It is made of a member having excellent heat dissipation properties that is heated by the heat transfer from the heat generating portion.

In the rice cooker according to a second aspect of the present invention, an upper surface of the plate member is coated with an insulating member.

(Operation) According to the configuration of claim 1, the lower surface side of the plate-shaped member becomes hot and emits mainly near-infrared rays at an early stage due to heat generation of the heat-generating portion, and this near-infrared rays pass through the communication space to the side of the container. The bottom side is heated, and the upper surface of the plate-like member is in a relatively low temperature state to radiate far-infrared rays. With this far-infrared ray, the bottom side of the container can be heated to cook rice.

In this case, the plate-shaped member is heated by the heat transfer from the heat-generating portion, and is made of a member having excellent heat dissipation. Therefore, the heat from the heat-generating portion is transferred to the plate-shaped member, and the plate-shaped member is heated. The infrared rays radiated from the plate-like member are far infrared rays near the heat absorption wavelength of the object containing almost no visible light, and the container can be efficiently heated. Further, by fixing the heat generating portion to the plate-like member, the heat of the heat generating portion can be transferred to the plate-like member very efficiently. Further, since the heat-generating portion is fixed to and integrated with the plate-shaped member, there is no need to separately incorporate the plate-shaped member and the heat-generating portion into the bottom space at the time of assembly, and the workability can be improved.

Further, according to the configuration of the second aspect, even if the heating element touches the heating element when the insulation resistance of the heating section decreases, safety can be ensured by the insulating member.

Embodiment Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a container body composed of an outer case 2 and an inner case 3,
The inner case 3 is made of an aluminum material that has been subjected to polishing or the like so as to increase the reflection efficiency of the inner surface. Reference numeral 4 denotes a pot-like container which is removably housed in the vessel body 1, and a flange portion 5 serving as an upper portion of the vessel 4 can be placed in close contact with an upper portion 6 of the vessel body 1, The container 4 is made of an aluminum material having excellent heat conductivity and subjected to black processing or the like for improving heat absorption. A side space 9 for heating is formed between the side 7 of the inner case 3 of the container body 1 and the side 8 of the container 4, and between the bottom 10 of the container main body 1 and the bottom 11 of the container 4. A bottom space 12 for heating is formed. 13 is the bottom space 12
And a heating element provided at the bottom 11 of the container 4.
A plate-like member 14 supported by a partition member described later so as to face substantially the entire surface of the plate-like member 14, and a heat-generating portion 16 such as a sheathed heater which is attached to the lower side of the plate-like member 14, that is, the lower surface 15 so as to open downward. Be composed. The plate-like member 14 has a high-temperature strength,
An insulating member 18 made of a ceramic material having heat resistance and high radiation properties is coated on the upper surface 17 thereof by thermal spraying or the like. The heat generating portion 16 is formed of a sheathed heater having a heat-resistant stainless steel member as an outer tube, and is provided integrally with the plate-like member 14 by a brazing portion 19 such as nickel brazing. Further, the heat generating portion 16 is provided in a spiral shape,
The temperature of the upper surface 17 of the plate-like member 14 is substantially uniform or slightly concentrated on the outer peripheral side so that the outer peripheral portion has a high temperature. A communication space portion 20 is formed between the side portion of the heating element 13, that is, the heating portion 16, the side portion of the plate member 14, and the side portion 7 of the inner case 3 of the container main body 1 to communicate in the up-down direction. .
Reference numeral 21 denotes a heat-sensitive portion that contacts the bottom 11 of the container 4. The heat-sensitive portion 21 is made of a material having excellent heat conductivity such as an aluminum material, and is provided in a mounting hole 22 formed in the center of the heating element 13. In addition, a heat sensitive element 23 such as a thermistor is provided on the lower surface of the heat sensitive part 21. The inside and outside of the heat sensitive portion 21 are partitioned by a partition member 24 made of ceramic or the like. The partitioned space is connected to the outside of the inner case 3 by a communication hole 25 formed in the bottom 10 of the inner case 3. 26 is a lid.

 Next, the operation of the above configuration will be described.

An appropriate amount of rice 27 and water 28 are weighed and put into container 4, and the container 4
Is stored in the container body 1, the heat-sensitive portion 21 abuts on the container 4, and the flange portion 5 comes into close contact with the upper portion 6. When a rice cooker switch (not shown) is operated, the heat generating portion 16 is energized to generate heat, and the generated heat heats the plate member 14 by heat transfer. At this time, since the heat generating portion 16 is provided substantially entirely on the plate-like member 14, the temperature distribution becomes uniform, there is no local heating, and deformation due to distortion due to local heating can be prevented. Further, radiant heat is radiated from the heat generating portion 16 directly to the bottom portion 10 side, and the lower surface 15 side of the heat generator 13 becomes higher in temperature than the upper surface 17 side.
Then, the heat radiated to the lower part 12A of the bottom space is
The container 4 is guided while being reflected to the side space 9 through the side wall 9 and heats the side 7 side of the container 4. At this time, the upper surface 17 side and lower surface 15 of the heating element 13
Since the heat capacity of the lower surface 15 side is smaller due to the open state of the heat generating portion 16 at the initial stage of energization, the rising speed becomes faster. Further, when the heating section 16 is in a red hot state, the heating element
The lower surface 15 of 13 is in a red-hot state and mainly emits near-infrared rays. In addition, the power density of the upper surface 17 is substantially reduced by the plate-like member 14, and the near-infrared rays are reduced by the insulating member 18 so that almost no visible light is radiated and far-infrared rays are mainly radiated. Accordingly, the temperature rise on the lower surface 15 shown in FIG. The upper X side in the container 4 is heated as in the case of cooking, and then the entire bottom 11 of the container 4 is efficiently heated by far infrared rays from the bottom space upper portion 12B due to the temperature rise on the upper surface 17 shown in FIG. The lower Y side in the container 4 is heated like a hot plate. This is because near infrared rays generally have a fast rising speed and become hot, but visible light energy loss results in lower heating energy than far infrared rays. However, it does not include visible light, is close to the heat absorption wavelength of the object, and has high heating energy efficiency. As a result, in the early stage of rice cooking, the upper X side in the container 4 is mainly heated and cooked, and then the lower Y side in the container 4 is heated and cooked. Because of the boiling, the unevenness of the cooked rice can be eliminated.

When the rice cooking is completed in this way, the heat in the container 4 is transmitted to the heat-sensitive element 23 via the heat-sensitive part 21 surrounded by the partition member 24, and when the predetermined temperature is reached, the heat-generating part 16 is cut off.
The temperature of the heating element 13 decreases relatively early, and a heat retaining heater (not shown) is energized to be kept warm.

As described above, in the above-described embodiment, the container 4 is housed in the container body 1 with the upper part 6 and the flange part 5 hermetically sealed, and the side parts 7, 8 and the bottom parts 10, 11 of the container body 1 and the container 4 are stored.
Side and bottom spaces 9, 12 are formed between the bottom spaces 12
In a rice cooker provided with a heating element 13 provided with a heating section 16,
By mounting the heat generating portion 16 on the lower surface 15 side of the heat generating member 13 and setting the lower surface 15 side to the high temperature side, the radiant heat on the lower surface 15 side of the heat generating member 13 provided with the heat generating portion 16 in the early stage of rice cooking allows the container 4 to be heated. By heating the side portion 8 and heating the bottom portion 11 of the container 4 from the upper surface 17 side of the heating element 13 during the rice cooking, uneven cooking can be eliminated and the temperature detection by the thermosensitive element 23 can be performed well. Can be. In addition, since the heat generating portion 16 is provided on the lower surface 15 side of the heat generating member 13, the heat generating portion 13 has excellent heat radiation properties, so that the heat generating portion 16 does not become hot and shortens the service life. Part 16
No separate components are required for thermal protection.

Further, since the plate-shaped member 14 is heated by heat transfer from the heat generating portion 16 and is made of a member having excellent heat dissipation, the heat from the heat generating portion 16 is transferred to the plate-shaped member 14 and heats the plate-shaped member 14. As a result, the infrared rays emitted from the plate-like member 14 are far infrared rays close to the heat absorption wavelength of the object containing almost no visible light, and the container 4 can be efficiently heated. Also,
By fixing the heat generating portion 16 to the plate member 14, the heat of the heat generating portion 16 can be transferred to the plate member 14 very efficiently. Furthermore, since the heat generating portion 16 is fixed to and integrated with the plate member 14, there is no need to separately install the plate member 14 and the heat generating portion 16 in the bottom space 12 at the time of assembly, and the workability can be improved.

Further, by providing the insulating member 18 on the upper surface 17 of the heating element 13, safety can be ensured even when touched by a hand or the like. In particular, when the heat generating portion 16 is a sheathed heater, the insulating member 18 can be used even if a hand or the like touches the heat generating member 13 due to moisture absorption or when the insulation resistance of the outer tube decreases at high temperature.
Danger can be eliminated.

In addition, since the heat-sensitive portion 21 is surrounded by the partition member 24, the heat-sensitive portion 21 is not affected by heat from the bottom space lower portion 12A, so that the temperature of the container 4 can be accurately detected. Since the inside is communicated by the communication hole 25, heat does not accumulate around the thermosensitive element 23, and the temperature can be detected more accurately.

Note that the present invention is not limited to the above embodiment,
For example, various modifications are possible, such as fixing the heat generating portion and the heat generating element by appropriate means other than brazing.

[Effect of the Invention] The rice cooker according to claim 1 of the present invention is formed with a vessel main body, a container placed and stored on the upper part of the vessel main body, and between the vessel main body and the side and bottom of the vessel. Heating side space and bottom space to be provided, a plate member provided in the bottom space and facing the bottom of the container, and the plate member such that the lower surface side of the plate member is higher in temperature than the upper surface side. A heat-generating portion fixedly provided on the lower side, and a communication space portion provided on a side portion of the plate-shaped member and communicating in a vertical direction, wherein the plate-shaped member is heated by heat transfer from the heat-generating portion. It is made of a member with excellent heat dissipation, which eliminates insufficient heating in the center of the container and eliminates uneven cooking. It can be carried out. Furthermore, since the heat capacity of the heating element can be reduced, the rising speed in the early stage of rice cooking can be increased, and the temperature of the rice can be lowered relatively quickly after the rice cooking, so that the rice cooking performance can be improved. Moreover, the container can be heated by transferring the heat of the heat generating portion to the plate member very efficiently, and the workability is excellent.

Further, in the rice cooker according to the second aspect of the present invention, since the upper surface of the plate-like member is coated with an insulating member, safety can be ensured even if a hand or the like touches the heating element.

[Brief description of the drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view, and FIG. 2 is a graph showing the temperature rise of the upper surface side temperature and the lower surface side temperature of the heating element. 1 ... container body 4 ... container 5 ... flange part (upper part) 6 ... upper part 7, 8 ... side part 9 ... side space 10, 11 ... bottom part 12 ... bottom space 14 ... plate shape Member 15 Bottom surface 16 Heat generating part 17 Top surface 18 Insulating member 20 Communication space

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) A47J 27/00-27/64

Claims (2)

(57) [Claims] 1. A container main body, a container mounted on the upper part of the container main body, and a heating side space and a bottom space formed between the container main body and the side and bottom of the container. A plate-shaped member provided in the bottom space and facing the bottom of the container; and a heat-generating portion fixedly provided below the plate-shaped member such that a lower surface side of the plate-shaped member has a higher temperature than an upper surface side. And a communication space portion provided on a side portion of the plate-shaped member and communicating in the up-down direction, wherein the plate-shaped member is made of a member excellent in heat radiation property heated by heat transfer from the heat generating portion. A rice cooker characterized by the following. 2. The rice cooker according to claim 1, wherein an insulating member is coated on an upper surface of the plate-shaped member.