JP3085863B2 - Electric rice cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
The present invention relates to an electric rice cooker provided with a protector for preventing the attachment of foreign substances and the like.

[0002]

2. Description of the Related Art As shown in FIG. 11, a conventional electric rice cooker has a rice cooker body 1 provided with an inner pot 2 made of aluminum die-cast, and a sheath heater 3 provided in a space below the inner pot 2 as shown in FIG. Heating the bottom of the inner pot 2 and heating the entire circumference by convection heat through a heating space on the outer periphery of the inner pot 2 to cook rice. This is described in Japanese Utility Model Publication No. 58-51844. ing. In addition, in FIG.
Is an inner lid, 6 is a reflector, and 7 is a thermostat.

However, in this type of electric rice cooker using a sheath heater as a heat source, the bottom portion of the inner pot 2 is heated and the entire circumference is heated by convection heat via a heating space. Heat conduction is inefficient, inner pot 2
In some cases, a temperature difference occurred between the bottom portion and the top portion, resulting in uneven cooking.

Also, an inner die 2 made of aluminum die-casting is used.
Since the heat reflectivity is large, the heat transfer from the heating space to the inner pot 2 is reduced, so that a large amount of heat cannot be supplied to the inner pot 2, so that the rice cooking time is long. Further, if the amount of heat radiation of the sheathed heater 3 is increased in order to shorten the rice cooking time, the amount of heat radiation from the rice cooker body 1 to the outside increases, so that the thermal efficiency is deteriorated and the sheathed heater 3 cannot withstand high temperatures and has a long life. There was a problem that was getting shorter.

Therefore, the present applicant has filed Japanese Patent Application No. Hei.
No. 50 proposes an electric rice cooker in which rice cooker performance is improved by using a heat source that generates electromagnetic waves instead of a sheathed heater. In this electric rice cooker, as shown in FIG. 12, a rice cooker body 10 has a glass inner pot 11 capable of transmitting electromagnetic waves therein, an inner frame 12 formed of a metal reflector, and a halogen lamp. The cooking water in the inner pot 11 is uniformly and uniformly heated by an electromagnetic wave from the rice cooking heater 13.

However, rice cooker 1 such as a halogen lamp
No. 3 is not as strong as a sheathed heater, and also has a problem of corrosion deterioration due to foreign matter adhesion. Therefore, rice cooker 1
In order to prevent foreign matter from adhering to the inner cover 3, a glass protective plate 1 that transmits electromagnetic waves between the inner pot 11 and the rice cooker 13
4 are arranged. In FIG. 12, reference numeral 15 denotes an outer lid,
Is an inner lid, 17 is a heater for keeping heat, and 18 is a thermostat.

[0007]

However, a protection plate 14 for preventing foreign matter from adhering to the rice cooker 13 is not provided.
Has a problem in that it absorbs a part of the electromagnetic wave transmitted from the rice cooker 13 and deteriorates the thermal efficiency by absorbing a part of the electromagnetic wave. In addition, the space below the protective plate 14 becomes high in temperature and the life of the rice cooker 13 may be shortened. .

[0008] Therefore, an object of the present invention is to provide an electric rice cooker that uses a movable protective plate to prevent foreign substances and the like from adhering to a rice cooker and to perform heating with good thermal efficiency.

[0009]

As shown in FIG. 1, the means for solving the problem according to the first aspect of the present invention comprises an inner pot 24 provided inside a rice cooker main body 21 and an electromagnetic wave arranged at an interval in the inner pot 24. , A protector 26 disposed between the inner pot 24 and the rice cooker 25 so as to be openable and closable, and an opening / closing means for opening and closing the protector 26.

According to a second aspect of the present invention, there is provided a protective body
Reference numeral 6 denotes a plurality of protection plates 26a to 26n.

According to a third aspect of the present invention, there is provided a simultaneous operation means for simultaneously moving a plurality of protection plates 26a to 26n.

According to a fourth aspect of the present invention, there is provided a control means for operating the opening / closing means in conjunction with the operation of the rice cooker.

According to a fifth aspect of the present invention, there is provided a protection device comprising:
No. 6 was subjected to a surface treatment having water repellency or lubricity.

[0014]

In the above means for solving the problems, a plurality of protection plates 26a to 26a-26 are operated by the operation of the rice cooker (for example, opening and closing the lid, turning on and off the rice cooker 25, detecting the heating temperature of the heating space, etc.).
n moves at the same time, and the protection body 26 opens and closes with a short movement distance. When the protection body 26 is open, the rice cooker 2
The electromagnetic wave from 5 can be directly supplied to the inner pot 24 without passing through the protection body 26, thereby performing heating with high thermal efficiency. When the protection body 26 is closed, the space between the inner pot 24 and the rice cooker 25 is shut off, so that adhesion of foreign substances and the like to the rice cooker 25 can be prevented. Even if a foreign substance or the like adheres to the protection body 26, it can be easily cleaned because the surface treatment having water repellency or lubricity is performed.

[0015]

【Example】

(First Embodiment) As shown in FIG. 1, an electric rice cooker according to a first embodiment of the present invention has a bottomed short tubular rice cooker main body 21, and an openable and closable lid 22 for covering an upper surface opening thereof. In the rice cooker main body 21, an outer cooker 23, an inner cooker 24 removably housed in the outer cooker 23, and a rice cooker 25 arranged below the inner cooker 24 for generating electromagnetic waves are provided. And an openable / closable protector 26 disposed between the inner pot 24 and the rice cooker 25 to prevent dust and foreign substances from adhering to the rice cooker 25.

The lid 22 is supported by the rice cooker body 21 so as to be rotatable around a pivot 21a, and forms an outer shell of the lid 22, and an inner pot attached to the inside of the outer lid 30. 2
4 and a hollow inner lid 31 that covers the upper opening.
A heat insulating material 32 is interposed between the outer lid 30 and the inner lid 31, and a steam hole 33 is formed at the center of the outer lid 30 and the inner lid 31 so as to penetrate vertically. On the upper surface of the inner cover 31, a heat retaining heater 34 is disposed, and on the lower surface of the inner cover 31, a seal packing 35 for sealing between the inner pot 24 and the inner cover 31 is attached.

The outer pot 23 has a reflective plate made of aluminum or aluminum alloy or the like having an inner surface with a high reflection efficiency and a specular gloss, and an upper edge thereof.
1 and the electromagnetic wave from the rice cooker 25
4 is arranged so as to reflect the light all around. At the center of the bottom of the outer kettle 23, a temperature sensor 40 which contacts the inner kettle 24 and detects the temperature of the inner kettle 24 is penetrated and held. A heat insulating material 41 is provided between the outer pot 23 and the rice cooker main body 21.
Is interposed.

The inner pot 24 has a short cylindrical shape with a bottom and is made of a metal having high thermal conductivity, heat resistance and impact resistance, such as aluminum or an aluminum alloy, and has a fluorine-based resin on its inner surface. Coating enhances cleanability. The inner hook 24 has an upper edge placed on the upper edge of the outer hook 23 and is housed with a gap around the outer hook 23.

The rice-cooking heater 25 is made of a heating element that generates an electromagnetic wave having a wavelength in the range from visible light to far-infrared rays. A halogen lamp, a xenon lamp, or the like is used. Mounted on the bottom.

As shown in FIG. 2, the protective body 26 is composed of a plurality of substantially drop-shaped protective plates 26a to 26n coated with a water-repellent or lubricious surface treatment material. Here, when a Tyranno coat manufactured by Ube Industries, Ltd. having a composition as shown in Table 1 is used as the surface treatment material, the protective plates 26a to 26n are formed by the action of the polytitanocarbosilane-based binder and the silicone oil in the composition. Even if it is contaminated by dust or foreign matter, it can be easily cleaned.

[0021]

[Table 1]

As shown in FIG. 3, each of the protection plates 26a to 26n passes through a through hole 23a formed in the side wall of the outer hook 23, and is fixed to an outer flange 45 of the outer hook 23. 46 are supported so as to be freely rotatable horizontally.
These protection plates 26a to 26n are arranged in the circumferential direction around the temperature sensor 40 so that they are adjacent to each other in a slightly inclined state, and are located at the same height.

Simultaneously operating means for simultaneously rotating the protection plates 26a to 26n horizontally is provided. The simultaneous operation means includes a gear 51 formed on the outer periphery of each protection plate 26a to 26n and a gear 51 And an annular gear 52 that meshes with. The annular gear 52 includes a cylindrical gear support 53 disposed between the outer pot 23 and the rice cooker main body 21.
The inner gear 54 formed on the inner peripheral surface of the protective plate 26a to 26n meshes with the gear 51 of each protective plate 26a to 26n, and the outer gear 55 formed on the outer peripheral surface thereof Forward / reverse rotatable drive motor 5 as opening / closing means for opening / closing
6 is engaged with the motor gear 57. The protection body 26 (each of the protection plates 26 a to 26 a) is driven by the drive motor 56.
n) is opened and closed, that is, by the forward rotation of the drive motor 56, each of the protection plates 26a to 26n
5 is switched from a closed position (a state shown in FIG. 2 (a)) for closing the space to an open position (a state shown in FIG. 2 (c)) for opening the space. , The structure is switched from the open position to the closed position.

As shown in FIG. 4, the electric rice cooker detects the opening of the rice cooker switch 60 and the protection plates 26a to 26n provided on the upper part of the rice cooker main body 21 for starting or stopping the rice cooker keeping process. Protection plate opening sensor 6
1, a protection plate closing sensor 62 and the like for detecting the closing of the protection plates 26a to 26n are provided, and the rice cooker 25 and the drive motor 56 are driven by the output signals of the sensors including the temperature sensor 40 to perform the rice cooker insulation process. A control means (control circuit) 63 comprising a microcomputer to be executed is provided.

The protection plate opening sensor 61 is composed of a microswitch (not shown) mounted on the inner surface of the outer lid 23, and is connected to one of the protection plates 26a to 26n when the protection plates 26a to 26n are in the open position. The opening of the protection plates 26a to 26n is detected by the contact of the formed projecting pieces (not shown). Similarly, the protection plate closing sensor 62 also
It consists of a microswitch (not shown) attached to the inner surface of the outer lid 23, and a projection (not shown) formed on one of the protection plates 26a to 26n abuts when the protection plates 26a to 26n are in the closed position. Protective plates 26a-
26n is detected. The protection plate opening sensor 61
Further, as the protection plate closing sensor 62, an optical sensor which is attached to the inner surface of the outer lid 23 and includes a light receiving and emitting element which is disposed to face one of the protection plates 26a to 26n may be used.

When the rice cooker switch 60 is turned on (the rice cooker keeping process is started), the control circuit 63 rotates the drive motor 56 forward to open the protection plates 26a to 26n, and the rice cooker switch 60 is turned off. When the rice cooker insulation process is stopped, the drive motor 56 is rotated in the reverse direction to close the protection plates 26a to 26n.

The operation of the rice cooking and warming process in the above configuration will be described with reference to FIG. First, a predetermined amount of washed rice and water are put into the inner pot 24, the inner pot 24 is stored in the outer pot 23, the lid 22 is closed, and then the rice cooker switch 60 is pressed (turned on). The drive motor 56 rotates forward, the motor gear 57 rotates left (rotates in the direction A), the annular gear 52 rotates right (rotates in the direction B) as shown in FIG. 2, and the protection plates 26a to 26n are fixed. A right rotation (rotation in the direction C) about the axis 46 switches from the closed posture to the open posture.

When the opening of each of the protection plates 26a to 26n is detected by the protection plate opening sensor 61, the rice cooking heater 25 is energized to execute the rice cooking process. The electromagnetic wave radiated upward from the rice cooker 25 passes through the space between the outer pot 23 and the inner pot 24 and is reflected directly or on the reflecting plate as the outer pot 23 to reach the side and bottom surfaces of the inner pot 24, Heat is quickly and uniformly transferred to the cooking water in the inner pot 24.

The steam generated by the rise in the temperature of the cooked water is supplied to a steam hole 33 at the center of the outer lid 30 and the inner lid 31.
Is discharged to the outside. As rice cooking progresses, inner pot 2
When the temperature in the inner pot 24 rises sharply due to the depletion of the water in the inner pot 4 and the temperature of the inner pot 24 reaches the cooked temperature, the temperature sensor 40
Detects this, the power supply to the rice cooking heater 25 is stopped, and the rice cooking is completed. After the rice cooking is completed, when the temperature of the inner pot 24 decreases and reaches the heat retaining temperature, the temperature sensor 40 detects this, and energizes the heat retaining heater 34 to raise the temperature of the rice in the inner pot 24 to 70 ° C.
Keep warm to a degree.

When the rice cooker switch 60 is pressed again (turned off) to stop the rice cooker warming process, the drive motor 56 rotates in the reverse direction, and the motor gear 5 as shown in FIG.
7 rotates clockwise (rotates in the direction D), the annular gear 52 rotates counterclockwise (rotates in the direction E), and the protective plates 26a to 26n rotate counterclockwise around the fixed shaft 46 (rotates in the direction F) to open. To the closed position. Thereby, the space between the inner pot 24 and the rice cooker 25 is shut off, and when the lid 22 is opened and the inner cooker 24 is removed, the rice cooker 25 is exposed and dust, foreign matter, etc. adhere. Can be prevented.

As described above, since the protector 26 can be freely opened and closed, when the protector 26 is opened, the rice cooker 25
The electromagnetic wave from is supplied directly to the inner pot 24 without passing through the protection body 26, so that heating with high thermal efficiency can be performed. Therefore, since the heat of the rice cooker 25 is quickly and uniformly conducted into the inner pot 24, the rice cook time can be shortened, and the rice can be evenly absorbed in the early stage of the rice cooker. The convection of the rice and the cooking water can be performed uniformly, and the temperature difference in the inner pot 24 becomes small, so that delicious cooked rice without uneven cooking can be obtained. Further, since a large amount of heat is input into the inner pot 24 without increasing the heat radiation amount of the rice cooker 25, the life of the rice cooker 25 can be extended. Moreover, the protective body 26
Is closed, foreign substances and the like can be prevented from adhering to the rice cooker 25.

The protection body 26 includes a plurality of protection plates 26a to 26a.
26n, each protection plate 26a-26
By moving n respectively, the protection body 26 can be opened and closed with a short movement distance, and the movement space of the protection body 26 is reduced, thereby enabling downsizing. Moreover, since the protection plates 26a to 26n are simultaneously moved, the opening and closing operation of the protection body 26 can be performed in a short time.

Further, by automatically opening and closing the protection body 26 in conjunction with the operation of the rice cooker switch 60, the protection body 26 is opened at the time of heating and closed at other times, so that the handling becomes easy.

The protective plates 26a to 26n are subjected to a water-repellent or lubricious surface treatment so that the protective plates 2a to 26n are protected.
When 6a to 26n is contaminated by foreign matter or the like, it can be easily cleaned.

(Second Embodiment) In an electric rice cooker according to a second embodiment, as shown in FIGS. 6 and 7, a lid comprising a microswitch or the like for detecting opening and closing of the lid 22 when the lid 22 is attached or detached. An open / close sensor 70 is provided on the upper part of the rice cooker main body 21, and when the closure of the lid 22 is detected, the control circuit 71 rotates the drive motor 56 forward to open the protection body 26, When the opening is detected, the drive motor 56 is rotated in the reverse direction to close the protection body 26.

Thus, when the lid 22 is closed (when the rice cooking and warming process is executed), the protective body 26 is opened, and when the lid 22 is opened, there is a possibility that foreign matter or the like may adhere to the rice cooking heater 25. The body 26 can be closed. In addition,
Other configurations and operations are the same as those of the first embodiment,
Members having the same functions as in the first embodiment are denoted by the same reference numerals.

(Third Embodiment) In an electric rice cooker according to a third embodiment, as shown in FIGS.
A heating space temperature sensor 75 such as a thermistor for detecting the temperature of the heating space between the heater and the heater is provided on the inner surface of the outer lid 23. The control circuit 76 sets the temperature of the heating space by starting heating by the rice cooker 25. When the temperature exceeds the predetermined value, the drive motor 56 rotates forward to open the protection body 26; when the temperature of the heating space falls below the set value, the drive motor 56 reversely rotates to close the protection body 26; When the power supply to the power supply 25 stops, the drive motor 56 is rotated in the reverse direction to close the protection body 26. The set value of the temperature of the heating space is room temperature or a temperature slightly higher than room temperature.

Thus, the protection body 26 can be opened when the rice cooker 25 is heating, and closed when the rice cooker 25 is not heating. Other configurations and operations are the same as those of the first embodiment, and members having the same functions as those of the first embodiment are denoted by the same reference numerals.

(Fourth Embodiment) In an electric rice cooker according to a fourth embodiment, as shown in FIG. 10, a protection body 80 is formed of four rectangular protection sheets coated with a water-repellent or lubricious surface treatment material. It is composed of plates 80a, 80b, 80c, 80d. FIG. 10A shows a state when the protection body 80 is opened, and FIG. 10B shows a state when the protection body 80 is closed.

Each protective plate 80a, 80b, 80c, 80d
Small holes S1 and S2 are formed in the center of the upper and lower portions, respectively. A movable guide line 81 is inserted into the upper hole S1 of each of the protection plates 80a, 80b, 80c and 80d, and the lower hole S2 is formed. The fixed guide wire 82 is inserted through the
(See (a)).

The movable guide wire 81 has both ends fixed to both outer protection plates 80a and 80d, and is disposed horizontally. Both ends of the fixed guide wire 82 are fixed to the side wall of the outer hook 23, and before and after the portion where the small hole S2 of the fixed guide wire 82 is inserted, each protective plate 80a,
A stopper 82a larger than the small hole S2 is fixed so that the lower portions of 80b, 80c, and 80d do not move more than a fixed amount with respect to the fixed guide line 82. Each protection plate 80a, 80
The arrangement intervals of b, 80c, and 80d are as follows: the small hole S1 and the small hole S2.
The length is almost equal to the distance between The movable guide line 81 and the fixed guide line 82 constitute a simultaneous operation means for simultaneously moving the protection plates 80a, 80b, 80c, 80d.

Further, the upper part of the protection plate 80a on one side and the outer hook 2
A coil 83 made of a shape memory intermetallic compound causing a martensitic transformation at a low temperature is interposed between the side wall of No. 3 and the upper part of the other protective plate 80d and formed outside the outer pot 23. Between the flange 84 and the bias spring 8
5 are interposed. The bias spring 85 is inserted through an insertion hole 86 formed in the side wall of the outer hook 23, and has a smaller spring constant than the coil 83. And
An opening / closing means for opening / closing the protection body 80 by the coil 83 and the bias spring 85 is configured. The protection plate 80
Even if a, 80b, 80c, and 80d try to rotate around the fixed guide wire 82, the bias spring 85 is in contact with the hole wall of the insertion hole 86 to prevent the rotation.

Then, the protection plates 80a, 80b, 80c, 80d (protector 80) held by the guide wires 81, 82, the coil 83, and the bias spring 85 as described above are placed between the inner pot 24 and the rice cooker 25. Are arranged in two rows with the temperature sensor 40 interposed therebetween. The number of protection plates is not limited to four, and may be any number.
b, 80c, and 80d may be arranged side by side on the circumference around the temperature sensor 40. In this case, the fixed guide wire 8
2, each of the protection plates 80a, 80b, 80c, 80
A thin annular member made of metal or heat-resistant synthetic resin that holds the lower part of d may be arranged so as not to block electromagnetic waves from the rice cooker 25.

Thus, depending on the temperature of the heating space between the outer pot 23 and the inner pot 24, the protective body 80 (protective plates 80a, 80a) is heated.
b, 80c, 80d) open and close, that is, at normal temperature, the biasing force of the bias spring 85 exceeds the coil 83,
The upper portions of the protection plates 80a, 80b, 80c, and 80d are pulled in the direction of the bias spring 85 and fall, and FIG.
As shown in the figure, each protection plate 80a, 80b, 80c, 80d
Is in a closed position to close the space between the inner pot 24 and the rice cooker 25, and when the temperature of the heating space rises due to the heating of the rice cooker 25, the formation recovery force of the coil 83 to the mother phase state is increased by the bias spring 85. The coil 83 which has exceeded the power and has been straightened returns to a coil shape, and the protection plates 80a, 8
The upper portions of 0b, 80c and 80d are pulled up in the direction of the coil 83 and rise up, and the protection plates 80a, 80b, 80c and 80d are in the open position as shown in FIG.
Members having the same functions as in the first embodiment are denoted by the same reference numerals.

As described above, the coil 83 and the bias spring 8
5, the protection plates 80a, 80b, 80c, and 80d can be opened and closed, so that the structure can be simplified and the manufacturing cost can be reduced as compared with the case where the drive motor 56 is controlled to be opened and closed as in the first embodiment. can do.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that many modifications and changes can be made to the above-described embodiment within the scope of the present invention. For example, the inner pot 24 may be made of glass that transmits electromagnetic waves, and the cooked water itself may be directly heated by the electromagnetic waves from the rice cooker 25. Further, in the fourth embodiment, the coil 83
Instead of this, a structure in which the protection plate 80 is opened and closed by a solenoid or the like may be used to control the driving of the solenoid or the like in conjunction with the operation of the rice cooker as in the first to third embodiments. Further, the plurality of protective plates need not be moved at the same time, and may be configured to be partially opened and closed according to the degree of cooking rice.

[0047]

As is clear from the above description, according to the first aspect of the present invention, since the protective body is openable and closable,
When the protective body is opened, the electromagnetic wave from the rice cooker can be directly supplied to the inner pot without passing through the protective body to perform heating with high thermal efficiency. Therefore, since the heat of the rice cooker is quickly and uniformly conducted into the inner pot, the rice cook time can be shortened, and delicious rice cooked without uneven cooking can be obtained. Further, since a large amount of heat is input into the inner pot even if the heat radiation amount of the rice cooker is not increased, the life of the rice cooker can be extended. In addition, when the protective body is closed, it is possible to prevent foreign substances and the like from adhering to the rice cooker.

According to the second and third aspects of the present invention, since the protective body is composed of a plurality of protective plates, the entire protective body can be opened and closed within a short moving distance by moving each protective plate. The movement space of the body is reduced, and the size can be reduced. In addition, since the protection plates are simultaneously moved, the opening / closing operation of the protection body can be performed in a short time.

According to the fourth aspect, the protective body is opened and closed in conjunction with the operation of the rice cooker, for example, when the lid is opened and closed, when the rice cooker is turned on and off, and the like. Can be opened to enable efficient heating by the rice cooker, and then the protective body can be closed to prevent foreign matter and the like from adhering to the rice cooker.

According to the fifth aspect, by applying a water-repellent or lubricious surface treatment to the protective body, it is possible to easily clean the protective body when it is contaminated by foreign substances or the like.

[Brief description of the drawings]

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

FIGS. 2A and 2B are diagrams showing an open / closed state of a protection body, where FIG. 2A shows a state where the protection body is closed, FIG. 2B shows a state where the protection body is performing opening / closing operation, and FIG.

FIG. 3 is a longitudinal sectional view of a support portion of the protection plate.

FIG. 4 is a control block diagram of the electric rice cooker.

FIG. 5 is a flowchart of a rice cooking and warming process.

FIG. 6 is a control block diagram of the electric rice cooker according to the second embodiment.

FIG. 7 is a flowchart of a rice cooking and warming process.

FIG. 8 is a control block diagram of an electric rice cooker according to a third embodiment.

FIG. 9 is a flowchart of a rice cooking / heating process;

FIG. 10 is a diagram showing an open / closed state of a protection body according to a fourth embodiment;
(A) when the protective body is opened, (b) when the protective body is closed

FIG. 11 is a configuration diagram of a conventional electric rice cooker.

FIG. 12 is a configuration diagram of another conventional electric rice cooker.

[Explanation of symbols]

 21 rice cooker main body 24 inner pot 25 rice cooker 26 protector 63, 71, 76 control means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-17812 (JP, A) JP-A-6-86731 (JP, A) JP-A-7-136059 (JP, A) 116924 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) A47J 27/00 103

Claims (5)

(57) [Claims] 1. An inner cooker provided inside a rice cooker main body, a rice cooker for generating electromagnetic waves arranged at a distance from the inner cooker, and an openable and closable arrangement between the inner cooker and the rice cooker. An electric rice cooker provided with a protective body and an opening / closing means for opening and closing the protective body. 2. The electric rice cooker according to claim 1, wherein the protector comprises a plurality of protective plates. 3. The electric rice cooker according to claim 2, further comprising a simultaneous operating means for simultaneously moving the plurality of protection plates. 4. The electric rice cooker according to claim 1, further comprising control means for operating the opening / closing means in conjunction with the operation of the rice cooker. 5. The electric rice cooker according to claim 1, wherein the protective body is subjected to a water-repellent or lubricious surface treatment.