JPS5845610Y2 - electric cooker - Google Patents

Description

[Detailed description of the invention] This invention relates to an electric cooking device such as an electric rice cooker in which an inner pot can be freely stored inside an outer pot, and is particularly suitable for cooking food such as rice that always tastes delicious regardless of the thermal expansion of the heating plate. It is used for cooking.

Generally, as shown in Fig. 1, an electric rice cooker has a frame 1, an outer pot 2 mounted in the frame, an inner pot 3 with a flat bottom that can be stored in the outer pot, and one side attached to the frame. It is composed of a lid body 4 which is pivotably supported and allows the openings of the outer pot and the inner pot to be opened and closed, and a heating plate 5 fixed to the inner bottom of the outer pot, and the inner pot is stored in the outer pot. At the same time, substantially the entire bottom surface of the inner pot is placed on the heating plate to heat the inner pot.

However, since the heating plate is formed into an annular shape by embedding a ring-shaped sheathed heater 6 on the outside of the aluminum alloy 5', the heating plate is not energized before the sheathed heater is energized as shown in Fig. 2. As shown in A, it is in a horizontal state and the entire surface is in contact with the bottom of the inner pot.

At the beginning of energization (immediately after the start of cooking), the sheathed heater expands thermally due to the heat generated by the energization and increases the diameter of the ring-shaped part, but the heat of the sheathed heater is not sufficiently transferred to the aluminum alloy. Because the heater is not
Its inner side is displaced downward by Δh, ).

As the rice cooking progresses, at the point when the rice cooking is completed, the heat of the sheathed heater is transferred and the aluminum alloy thermally expands, and contrary to the above, the inside of the heating plate is lower than the position before electricity is applied (+ It is displaced upward by Δh2).

Furthermore, when the temperature of the heating plate returns to the temperature before the sheathed heater was energized after rice cooking is completed, the top surface of the heating plate returns to almost its initial position, but it remains permanently deformed by (+Δha) from its initial position, causing long-term damage. This (10Δh3) gradually increases with use.

This is because the structure of the sheathed heater is an iron pipe with nichrome wire and magnesia inside, so the thermal expansion coefficients of the above-mentioned iron and the aluminum alloy into which the sheathed heater is cast are different, causing the above-mentioned deformation. Became.

Therefore, when the heating plate is displaced as mentioned above, the contact with the inner pot becomes unstable, and (+△h3) increases with long-term use, so that only the center side of the bottom of the inner pot becomes unstable during rice cooking. (10△h3), the result is that it comes into contact with the inside of the displaced hot plate, but does not come into contact with the outside of the hot plate.

As a result, the center of the inner pot, which was in constant contact with the heating plate, was overcooked, and the outside, which was not in contact, was undercooked, resulting in uneven rice with a mountain-shaped bulge in the center of the top after the rice was cooked.

The present invention is intended to improve the above-mentioned drawbacks, and will be explained below with reference to the drawings of FIGS. The bottom cylindrical outer pot 10 is an annular aluminum alloy heating plate having a circular hole 11 in the center fixed to the inner bottom surface of the outer pot 7, and has a ring-shaped sheathed heater 12 buried therein as a heat source. A continuous protrusion 13 that protrudes inward and upward from the upper surface where the sheathed heater 12 is located is integrally molded, and its outer diameter is set to be approximately the same as the inner diameter of the outer pot 7.

Reference numeral 14 denotes an inner pot that can be freely stored in the outer pot 7. The bottom surface of the inner pot 14 is provided with an upwardly curved curved portion 15, with the center portion protruding the most.

The curved portion 15 has a dimension l between the upper surface of the heating platen 10 and the top of the curved portion 15, which is equal to the upward displacement (+△h2) of the inside of the heating platen 10 before the rice cooking is completed, and the remaining permanent strain (+ △
h3) is set to be larger than the sum of (△h2+△h3).

Reference numeral 16 denotes a heat sensitive element installed in the bulged portion 9, which is always urged by a spring 17 so as to protrude from the through hole 8.

Reference numeral 18 denotes a backing interposed between the hole wall of the circular hole 11 of the heating plate 10 and the outer wall of the bulging portion 9.

Next, to describe the fixing structure and function and effect of the hot platen, the hot platen 10 is fixed by screwing and fixing a mounting boss (not shown) provided on the bottom surface of the hot platen 10 to the inner bottom surface of the outer pot 7. However, as the hot platen 10 is moved closer to the circular bottom surface of the outer pot 7 due to this fixing, the outer periphery of the hot platen 10 comes into close contact with the inner wall of the outer pot 7 and the backing 18 is pressed against the hole wall of the circular hole 11. and bulge 9
Pressure is applied in between.

Then, the inner pot 14 containing rice and water is housed in the outer pot 7, and the outer part of the bottom surface of the inner pot 14 (the outer side of the curved part 15) is placed on the protruding part 13 of the heating plate 10.

At this time, the inner pot 14 and the heating plate 10 come into contact with each other through the protrusion 13, and the heat sensitive element 16 protruding from the bulge 9 brings its head into close contact with the center of the curved portion 15 by the spring 17.

Therefore, when electricity is applied to the sheathed heater 12 and the heating plate 10 is heated, the inside of the heating plate will be displaced downward as shown in the opening in Fig. 2 at the initial stage of energization, and the inside of the heating plate will be displaced downward before the rice cooking is completed. After the cooking is completed, the upward displacement (+△h3) of the inner side remains as a permanent strain, but when the inner pot 14 is displaced as described above, the bottom surface of the inner pot 14 is distorted by the protrusion 13 of the heating plate 10. Since it is in line contact with the heat exchanger, it is completely unrelated to its displacement and always carries out stable heat transfer.

Since the displacement (+△h3) remaining as permanent strain is also suppressed within the curved part 15 of the inner pot 14, the inside of the heating plate 10 does not come into contact with the bottom surface of the inner pot 14, and the center of the inner pot 14 Prevent overheating.

Furthermore, during rice cooking, the bottom surface of the inner pot 14 is heated by the heat from the outer pot 7 transferred from the heating plate 10 due to the contact part with the protruding part 13 and the side surface by the contact between the outer periphery of the heating plate 10 and the inner wall of the outer pot 7. Therefore, the outer wall surface of the inner pot 14 is effectively heated to achieve uniform cooking, and the rice cooking operation starts quickly when the outside temperature drops such as in winter.

Furthermore, by setting the contact position between the bottom surface of the inner pot 14 and the protrusion 13 of the heating plate 10 inside the position of the sheathed heater 12, the heat of the sheathed heater 12 is distributed around the sheathed heater 12 as shown in FIG. The heat conducted to the left side (outside) is transferred to the inner wall of the outer pot 7, and the heat conducted to the right side (inside) heats the inner pot 14 via the protrusion 13, making the heat generated by the sheathed heater 12 effective. This will be communicated to each part.

The protruding portion 13 prevents moisture attached to the outer wall of the inner pot 14 from entering the inside of the heating plate 10 when it falls onto the heating plate 10.

Although the present invention embeds a sheathed heater in the heating plate, it is not necessarily limited to a sheathed heater, and for example, a non-gang-shaped mica heater or the like may be covered with an aluminum plate.

As described above, the present invention includes an inner pot that can be freely stored in an outer pot, and a heating plate that is fixed to the inner bottom of the outer pot and has a heat source inside, and the upper surface of the heating plate where the heat source is located. In addition to providing a protruding part that protrudes more inwardly and upwardly, the outer peripheral edge of the heating plate is brought into close contact with the inner wall of the outer pot, and the bottom surface of the inner pot is placed on the protruding part. Displacement inside the heating plate is absorbed by the protrusion of the heating plate, so that the inner pot can be heated stably at all times.

In other words, the disadvantage that the contact position between the heating plate and the inner pot due to the displacement of the heating plate is concentrated at the center of the bottom of the inner pot as in the conventional method is eliminated, and the food to be cooked can be cooked uniformly and deliciously.

As mentioned above, this uniform cooking of the food is achieved by bringing not only the bottom of the inner pot but also the outer edge of the heating plate into close contact with the outer pot, transferring the heat from the heating plate to the outer pot, and heating from the sides of the inner pot as well. Furthermore, since the inner pot and heating plate are placed on a protrusion provided inside the top surface where the heat source is located, the heat from the heat source is unevenly distributed in only one direction of the heating plate. Effective heating is carried out by distributing heat to the protruding portion of the contact portion with the inner pot and the inner wall of the outer pot at a rate necessary to heat the inner pot without causing excessive conduction.

The bottom surface of the inner pot forms a curved part that curves upward, and the dimension between the top surface of the heating plate and the top of the curved part when the bottom surface of the inner pot is placed on the protruding part of the heating plate is determined by the heating plate. Since it is set to be larger than the displacement dimension on the inside of the heating plate, the inside of the heating plate becomes the inner pot due to the permanent strain that is accumulated by upward displacement inside the heating plate and the upward displacement when the heating plate is heated. to prevent contact with the bottom of the

Furthermore, the curved portion of the inner pot can prevent deformation due to foreign objects when the inner pot is taken out from the outer pot and placed on a table, etc., and the protruding portion prevents the upper surface of the heating plate and the inner pot from being deformed. The space defined by the dimension 1 with respect to the curved portion serves as a relief when rice grains or the like are attached to the upper surface of the heating plate, and has many excellent effects such as preventing deformation of the inner pot.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the electric rice cooker, and Figure 2 A to 2 are the first
An explanatory diagram showing the state of displacement due to thermal expansion of the heating plate shown in the figure, Figure 3 is a sectional view of the main part of an electric rice cooker which is an embodiment of the electric cooker of the present invention, and Figure 4 is an explanation of the operation of the main part. It is a diagram. 7...Outer pot, 10...Heating plate, 12...
... heat source, 13 ... protrusion, 14 ...
...Inner pot, 15...Curved part.

Claims (2)

[Scope of utility model registration request] (1) A cylindrical outer pot with a bottom, an aluminum alloy heating plate fixed to the inner bottom surface of the outer pot, which has an internal heat source and is formed into an annular shape with a circular hole in the center; It consists of an inner pot that can be freely stored in the pot, and a protrusion that protrudes upward inward from the upper surface of the heating plate where the heat source is located, and the outer periphery of the heating plate located outside the heat source is connected to the inner wall of the outer pot. An electric cooking device characterized in that the bottom surface of the inner pot is placed on a protruding portion. (2) In the electric cooker according to claim 1 of the above-mentioned utility model registration, the bottom surface of the inner pot forms a curved part that curves upward, and the bottom surface of the inner pot is placed on the protruding part of the heating plate. The heating plate is characterized in that the dimension between the upper surface of the heating plate and the upper part of the curved portion when placed is set to be larger than the displacement dimension inside the heating plate.