Rice cooker

Abstract

To provide a rice cooker that can be made lightweight while the strength of a lid body is reinforced.SOLUTION: A rice cooker 100 according to the present invention comprises: a bottomed cylindrical pot 5; an inner lid 26 covering an opening part of the pot 5; a heat dissipation plate 24 of which a surface on the side of the pot 5 is in contact with the inner lid 26; and a lid heater 31 arranged on a surface of the heat dissipation plate 24 on the side of an outer lid 22, and heating the inner lid 26 via the heat dissipation plate 24. The heat dissipation plate 24 includes a steel plate that is a base material Lm, a ceramic layer Lc located in a surface of the heat dissipation plate 24, and an aluminum alloy layer La located between the base material Lm and the ceramic layer Lc.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a rice cooker that can heat an inner lid that covers an opening of a pot that contains food to be cooked. [Background technology]

[0002] In order to prevent the inner lid from cooling and suppress condensation on the inner lid during cooking or keeping rice warm, the applicant of the present application has proposed a rice cooker in which the underside of the lid body (31) is made of a heat sink (34) made of a metal such as aluminum, a lid heater (36) is provided on the heat sink (34) on the inside of the lid body (31), the inner lid (56) is brought into contact with the heat sink (34), and the lid heater (36) heats the inner lid (56) via the heat sink (34) (see, for example, Patent Document 1). In the rice cooker of Patent Document 1, the entire surface of the inner lid (56) is uniformly heated by radiant heat from the heat sink (34), and a metal plate such as aluminum with excellent thermal conductivity is selected as the material for the heat sink (34). On the other hand, to strengthen the lid body (31), high-strength lid reinforcing plates (411, 412) made of a metal material are provided inside the lid body (31). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-157757 Summary of the Invention [Problem to be solved by the invention]

[0004] In the rice cooker of Patent Document 1, in order to compensate for the strength of the lid body (31), the lid reinforcing plates (411, 412) are made of a metal material that is more rigid than the lid body (31), which has the problem of significantly increasing the weight of the lid body (31).

[0005] In view of the above circumstances, the present invention aims to provide a rice cooker that can improve the strength of the lid while reducing its weight. [Means for solving the problem]

[0006] The rice cooker of the present invention comprises a cylindrical pot with a bottom, an inner lid that covers the opening of the pot, a heat sink that contacts the inner lid on one side, and a heating means that is arranged on the other side of the heat sink and heats the inner lid via the heat sink, and is characterized in that the heat sink includes a steel plate as a base material, a ceramic layer located on the surface of the heat sink, and an aluminum alloy layer located between the steel plate and the ceramic layer. [Effects of the Invention]

[0007] According to the present invention, the strength of the entire lid body can be improved, and the weight of the lid body can be reduced by reducing or eliminating the lid reinforcing plate. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of a rice cooker showing one embodiment of the present invention. [Figure 2] FIG. [Figure 3] FIG. 1 is a perspective view of the rice cooker with the outer lid removed. [Figure 4] FIG. [Figure 5] 1A is a perspective view of the rice cooker with the lid open, and FIG. 1B is a perspective view of the rice cooker with the lid open and the inner lid assembly removed. [Figure 6] FIG. 10 is a cross-sectional image of the heat sink. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, preferred embodiments of the cooking device of the present invention will be described with reference to the accompanying drawings. Note that common parts are designated by common reference numerals throughout the drawings.

[0010] FIGS. 1 to 6 show a rice cooker 100 according to one embodiment of the present invention. First, referring to FIGS. 1 to 3, the overall configuration of rice cooker 100 according to this embodiment will be described. Reference numeral 1 denotes a main body, which, when viewed from above, has a generally rectangular shape with a front, rear, left, and right sides facing each other, and is open at the top. Reference numeral 2 denotes a lid that can be opened and closed to cover the top opening of main body 1. Similar to main body 1, lid 2 also has a generally rectangular shape with a front, rear, left, and right sides facing each other, and a generally flat top. Main body 1 has an outer frame 3, which is an exterior component, and a pot housing 4 with an open top. When lid 2 is opened, a cylindrical pot 5 with a bottom, which serves as a container for water and rice to be cooked, is removably housed in pot housing 4. The pot storage section 4 is composed of an upper frame 6, which forms the top and side sections and is made of a heat-resistant material such as glass fiber-reinforced PET resin for suspending the pot 5, and a bowl-shaped inner frame 7 made of resin, and the entire section is formed into a cylindrical shape with a bottom.

[0011] Pot 5 has a main material 8 made of aluminum, which has good thermal conductivity, and a heating element 9 made of a magnetic metal plate such as ferritic stainless steel, joined to the outer surface of main material 8 from the lower side to the bottom. Additionally, on the outer surface of inner frame 7, which faces the lower side of pot 5 toward the bottom, a heating coil 11 is provided as a heating means for electromagnetic induction heating of heating element 9 of pot 5. When high-frequency current is supplied to heating coil 11, the alternating magnetic field generated by heating coil 11 causes heating element 9 of pot 5 to heat, thereby heating the food inside pot 5 during cooking and keeping warm. Additionally, pot sensor 12, which serves as a pot temperature detection means, is disposed in the center of the bottom of inner frame 7 so that it comes into elastic contact with the outer bottom surface of pot 5.

[0012] The top surface of the lid 2 is formed with a steam vent 14 that discharges steam generated from the food being cooked in the pot 5 to the outside of the rice cooker 100. In addition, a lid operating body 15 serving as a lid opening means is disposed in an exposed state in front of the top surface of the lid 2.

[0013] In addition to the steam vent 14 and lid operating member 15, a display operation unit 17 is provided on the top surface of the lid 2. The display operation unit 17 is mainly composed of display means 18, such as an LCD (Liquid Crystal Display), for displaying various information related to rice cooking, operation means 19, such as a push-button switch for starting rice cooking and selecting the cooking course, and a control PC (Printed Circuit) board 20 equipped with a control IC (not shown) for controlling the display means 18, operation means 19, and each part of the display operation unit 17. An operation panel 21 is also provided above the display operation unit 17 to protect the display means 18, operation means 19, and control PC board 20.

[0014] The lid body 2 is configured to have an outer lid 22 which is an exterior component, and an outer lid cover 23 which forms the lower part of the outer lid 22. The outer lid cover 23 is provided with a heat sink 24 which will be described later.

[0015] An inner lid assembly 25 is disposed below the lid 2 as a lower component of the lid 2. The inner lid assembly 25 is made of a metal material and has a disk-like shape with approximately the same diameter as the upper opening of the pot 5. The inner lid assembly 25 includes an inner lid 26 that covers the upper opening of the pot 5 and a lid gasket 27, which is an elastic member attached to the entire outer periphery of the inner lid 26 to seal the gap between the inner lid 26 and the pot 5. The annular lid gasket 27 is formed, for example, from silicone rubber or fluororubber. When the lid 2 is closed as shown in FIG. 1 , it abuts against a flange 28, which forms the top surface of the pot 5, or against the inner surface of the upper end of the pot 5, thereby sealing the gap between the pot 5 and the inner lid 26 and sealing out steam generated from the pot 5. The inner lid 26, made of a metal such as stainless steel or anodized aluminum, is disposed outside the heat sink 24.

[0016] A cord-like lid heater 31 serving as lid heating means for heating the inner lid 26 is insulated with, for example, silicone rubber and is provided on the surface of heat sink 24 facing the outer lid 22 inside lid body 2. A thermistor-type lid temperature sensor 32 for controlling the temperature of the inner lid 26 using lid heater 31 is also provided on the surface of heat sink 24 facing the outer lid 22. When cooking rice or keeping it warm, lid heater 31 heats the inner lid 26 via heat sink 24, preventing parts of the inner lid 26 and lid gasket 27 that are exposed to the inside of the pot 5 from cooling and preventing condensation on the surface of the inner lid 26 or the sides of the pot 5.

[0017] In addition to the lid heater 31 and lid temperature sensor 32, a pressure adjustment section 33 that adjusts the pressure in the space inside the pot 5 is also provided inside the lid body 2, and a steam exhaust path 34 that connects the steam port 14 and the pressure adjustment section 33 is formed as a passageway for releasing steam generated inside the pot 5 to the outside.

[0018] Pressure adjustment unit 33 is provided with a pressure adjustment valve 35 that opens and closes steam exhaust path 34 between the inside of pot 5 and steam vent 14. Pressure adjustment valve 35 works in conjunction with a solenoid 36 provided inside lid 2, and solenoid 36 moves pressure adjustment valve 35 up and down so that steam exhaust path 34 is opened when steam inside pot 5 is to be released to the outside, and steam exhaust path 34 is closed when the pressure inside pot 5 is to be pressurized or reduced. When pressurizing, high-frequency current is passed through heating coil 11 to heat the food to be cooked in pot 5, causing the food to boil and generate steam. This steam fills pot 5, and when the internal pressure of pot 5 reaches a predetermined value, spring 37 provided inside pressure adjustment valve 35 contracts upward against its elastic force, causing pressure adjustment valve 35 to move upward and open steam exhaust path 34, thereby maintaining the pressure inside pot 5 at or above atmospheric pressure.

[0019] Reference numeral 38 denotes a unitized heating board assembly disposed inside the main body 1 and including heating control means 39. Heating control means 39 is configured to include a microcomputer (microcomputer) equipped with a control IC such as a CPU, readable and writable memory for storing various information and data, and a timer for measuring rice cooking times in combination with the display operation unit 17 to electrically control each part of the rice cooker 100. Specifically, heating board assembly 38 is connected to the display operation unit 17, and heating control means 39 receives temperature detection signals from the pot sensor 12 and the lid temperature sensor 32, outputs heating control signals to the heating coil 11 and the lid heater 31, respectively, and outputs a drive control signal to the solenoid 36 that operates the pressure regulating valve 35.

[0020] Reference numeral 41 denotes a hinge portion, which has a hinge shaft 42 provided at the rear lower part of the lid body 2, and a hinge spring 43 formed of a coil spring or the like provided at the upper rear part of the main body 1. When the lid body operating body 15 provided on the front upper surface of the lid body 2 is pushed, the engagement between the main body 1 and the lid body 2 is released, and the lid body 2 is opened by the hinge spring 43 with the hinge shaft 42 as the center of rotation.

[0021] Hinge shaft 42 pivotally supports main body 1 and lid 2 so that they can be opened and closed freely, and hinge spring 43 is engaged with outer lid cover 23 and constantly urges lid 2 in the opening direction. A clamp 45 that moves in conjunction with lid operating body 14 is disposed on approximately the opposite side of hinge shaft 42, which serves as the rotation center of lid 2, and this clamp 45 is pivotally supported on outer lid cover 23 by a clamp shaft 46. Furthermore, on the outer frame 3, on approximately the opposite side of hinge portion 31, a clamp receiver 47 (see FIG. 4) that engages with clamp 45 is provided.

[0022] Clamp 45 provided on lid 2 rotates around clamp shaft 46 as a central axis and engages with clamp receiver 47 provided on main body 1. The engagement between clamp 45 and clamp receiver 47 maintains the main body 1 and lid 2 in a closed state. On the other hand, when lid 2 is to be opened, lid operating body 15 is pushed to rotate clamp 45 in the opposite direction, thereby releasing the engagement between clamp 45 and clamp receiver 47.

[0023] Reference numeral 48 denotes a pressure reducing means for lowering the pressure inside pot 5 below normal atmospheric pressure when lid 2 is closed on main body 1. After pot 5 is placed in pot housing 4 and lid 2 is closed, pressure reducing means 48 energizes solenoid 36 to move pressure regulating valve 35 downward, closing steam exhaust path 34 and reducing the internal pressure of sealed pot 5. When the pressure inside pot 5 drops below atmospheric pressure by a certain value, pressure reducing pump 49, which powers pressure reducing means 48, stops operating, maintaining the pressure inside inner pot 1 at a reduced pressure. Furthermore, when the pressure inside pot 5 is to be restored from the reduced pressure state to the same pressure as the outside air, pressure reducing pump 49 stops operating and a path (not shown) connecting pressure reducing pump 49 to the inside of pot 5 is opened. In other words, pressure reducing means 48 also serves as a pressure return means for restoring the pressure inside pot 5 from the reduced pressure state to the same pressure as the outside air.

[0024] A pair of lid reinforcing plates 51, 52, divided into left and right halves, are arranged on the outer lid cover 23, which is the base material of the lid 2. These lid reinforcing plates 51, 52 are intended to supplement the strength of the lid 2 and are made of, for example, a metal material that has higher rigidity than the synthetic resin outer lid cover 23, and are linearly shaped extending in the front-to-rear direction of the lid 2 along both side surfaces of the outer lid cover 23. The lid reinforcing plates 51, 52 are structured to be fixed to the outer lid cover 23 by fastening members such as screws.

[0025] Holes 53, 54 through which the clamp shaft 46 passes are provided on the front sides of the lid reinforcing plates 51, 52, and the clamp shaft 46 is connected to the lid reinforcing plates 51, 52 by passing each end of the clamp shaft 46 through these holes 53, 54. Holes 55, 56 through which the hinge shaft 42 passes are provided on the rear sides of the lid reinforcing plates 51, 52, and the hinge shaft 42 is connected to the lid reinforcing plates 51, 52 by passing each end of the hinge shaft 42 through these holes 55, 56. The hinge shaft 42 and the clamp shaft 46 are both metal members arranged in the left-right direction of the lid 2 and, by extension, the rice cooker 100. The combination of these members with the lid reinforcing plates 51, 52 effectively reinforces the lid 2 against pressure increases when the pressure inside the pot 4 exceeds atmospheric pressure, for example, during rice cooking, and against pressure decreases when the pressure drops below atmospheric pressure. Furthermore, by using the clamp shaft 46 as a connecting body, effective reinforcement of the clamp 45 is achieved with the minimum necessary structure, and by using the hinge shaft 42 as a connecting body, effective reinforcement of the rotation mechanism between the lid body 2 and the main body 1 is achieved with the minimum necessary structure.

[0026] Figure 4 is a perspective view of inner lid assembly 25, which essentially corresponds to the inner lid of this embodiment. Referring to this figure, reference numeral 61 denotes a steam exhaust hole that communicates with steam exhaust path 34, and pressure regulating valve 35 opens and closes steam exhaust path 34 by opening and closing hole 61. Reference numeral 62 denotes a pressure reduction hole that communicates with vacuum pump 49, through which vacuum pump 49 reduces the internal pressure of pot 5. Reference numeral 63 denotes an insertion portion that can be inserted into positioning portion 68-3, which will be described later.

[0027] The insertion portion 63 is made of resin and is formed in an approximately plate-like shape with a roughly kamaboko shape when viewed from above. This makes it easier to insert the insertion portion 63 into the positioning portion 68-3 when the inner lid assembly 25 is attached to the lid body 2, and also makes it less likely for the insertion portion 63 to become misaligned after insertion, improving its stability.

[0028] Reference numeral 64 denotes an inner lid engaging portion with which an inner lid engaging portion 68-4 (described later) can engage. In this embodiment, the inner lid engaging portion 64 is made of resin and formed in a generally plate shape, and is configured so that the inner lid assembly 25 is fixed to the outer lid cover 23 of the lid body 2 by inserting the insertion portion 63 into the positioning portion 68-3 and engaging the inner lid engaging portion 68-4 with the inner lid engaging portion 64.

[0029] Reference numerals 65 and 66 denote resin handles provided near the left and right sides of the inner lid engagement portion 64. When attaching the inner lid assembly 25 to the outer lid cover 23, the user can hold the handles 65 and 66 to perform the installation work without touching the inner lid 26 or lid gasket 27, and can also prevent the user from getting the inner lid assembly 25 upside down during installation.

[0030] Figure 5 is a perspective view of the rice cooker 100 with the lid body 2 open, with Figure 5(A) showing the state with the inner lid assembly 25 attached and Figure 5(B) showing the state with the inner lid assembly 25 removed. Referring to this figure, 68 is a recess provided on the bottom surface of the outer lid cover 23. The recess 68 is mainly composed of an inner lid accommodation recess 68-1 in which the inner lid assembly 25 is accommodated, a pot sealing recess 68-2 provided on the bottom surface of the lid body of the inner lid accommodation recess 68-1, that is, on the front side in Figure 5, a positioning portion 68-3 into which the insertion portion 63 can be inserted and held, and an inner lid locking portion 68-4 into which the inner lid locking portion 64 can be locked.

[0031] The interior of the inner lid accommodating recess 68-1 is integrally formed with a substantially cylindrical space and a space for the insertion portion 63, and a cylindrical mechanism portion 71 protrudes into this space from the bottom surface of the outer lid cover 23. The heat sink 24, lid temperature sensor 32, pressure adjustment portion 33, etc. are disposed on the bottom surface of this mechanism portion 71, and a steam exhaust path 34 is formed near the center of the mechanism portion 71. When the inner lid assembly 25 is accommodated in the inner lid accommodating recess 68-1 and attached to the recess 68, the heat sink 24, lid temperature sensor 32, and pressure adjustment portion 33 abut against the inner lid 26, blocking the opening of the steam exhaust path 34. The heat sink 24 abuts against the inner lid 26 on its entire surface, allowing heat from the heat sink 24 to be efficiently transferred to the inner lid 26. The diameter of the mechanism part 71 may be formed to be approximately the same as the inner diameter of the pot 5, allowing heat to be efficiently transferred to the part of the inner lid 26 above the pot 5, and also allowing the inner lid 26 to suppress temperature imbalances caused by uneven heat transfer from the heat sink 24.

[0032] In addition to the generally cylindrical space, the pot sealing recess 68-2 integrally forms spaces for the handles 55, 56, the clamp 45, and the insertion portion 63. The lid gasket 27 contacts the flange 28 and the inner surface of the upper end of the pot 5 within the space within the pot sealing recess 68-2, allowing the inner lid 26 to cover the upper opening of the pot 5. In this embodiment, the space for the insertion portion 63 within the inner lid receiving recess 68-1 and the space for the insertion portion 63 within the pot sealing recess 68-2 are generally identical in top view and are integrally formed. When the lid body 2 is closed, the space within the pot sealing recess 68-2 is maintained in a generally sealed state, preventing heat from the top of the pot 5 and the inner lid 26 from radiating outside the apparatus through the space within the pot sealing recess 68-2.

[0033] The inner lid locking portion 68-4 holds the inner lid assembly 25 in the recess 68 by locking the inner lid locking receiving portion 64. The inner lid locking portion 68-4 is provided at the front of the recess 68 and is configured to be located at the top of the bottom surface of the lid body 2 when the lid body 2 is open, as shown in Figure 4, so that when attaching the inner lid assembly 25 to the outer lid cover 23, the inner lid locking receiving portion 64 can be easily pressed into the inner lid locking portion 68-4 to lock it.

[0034] The positioning portion 68-3 positions the inner lid assembly 25 in the width direction and thickness direction in the lid body 2 by inserting and holding the insertion portion 63. The positioning portion 68-3 is made of resin and is provided in the curved portion at the rear of the recess 68, and is configured to be located at the bottom of the lid body 2 when the lid body 2 is open, as shown in Figure 5, making it easy to insert the insertion portion 63 into the positioning portion 68-3 when attaching the inner lid assembly 25 to the outer lid cover 23.

[0035] 6 shows a cross section of the heat sink 24, which is depicted as a simplified image for the purpose of explanation. As shown in the figure, the heat sink 24 of this embodiment is made of a steel plate material as a base material L. m The surface of the heat sink 24 is covered with a ceramic layer L such as aluminum oxide (Al2O3). c is located. And the base material L m The steel layer and the ceramic layer on the surface are c Between them, an intermediate layer is formed, for example, of an aluminum alloy layer L whose main component is an alloy of aluminum and iron. a Therefore, the heat sink 24 is configured by providing a ceramic layer L on the surface. c This allows for high heat radiation, and the heat can be efficiently dissipated to the inner lid 26 in the same way as with conventional anodized aluminum coatings. a In addition to the properties of high corrosion resistance and thermal conductivity due to the m The strength of this steel plate is significantly higher than that of conventional heat sinks made only of aluminum. Therefore, compared to conventional heat sinks made only of aluminum, it is possible to draw deeper, and the base material L m By adding the shape to the material strength of the heat sink 24, the strength of the heat sink 24 can be further improved. In addition, the heat sink 24 is located in the center of the underside of the mechanism part 71 and covers most of the center of the underside, improving the strength of the recess 68 in which the mechanism part 71 is provided, i.e., the outer lid cover 23 that forms the lower part of the lid body 2, and improving the strength of the entire lid body 2. In this embodiment, the ceramic layer L c is aluminum oxide, aluminum alloy layer La The ceramic layer L is an alloy of aluminum and iron. c is made of a material with high thermal radiation properties, and the aluminum alloy layer L a is made of a material with high corrosion resistance and thermal conductivity, and the base material L m The present invention is not limited to this configuration, as long as the steel plate has high strength.

[0036] As shown in FIG. 6, the heat sink 24 has an aluminum layer L Al The heat sink 24 may be made of a hot-dip aluminized steel sheet. c and aluminum alloy layer L a The ceramic layer L has excellent heat resistance. c , aluminum layer L Al and aluminum alloy layer L a The aluminum alloy layer L has excellent corrosion resistance. a This makes it possible to create a heat sink 24 that is excellent in abrasion resistance and has excellent overall heat reflectivity.

[0037] The heat sink 24 may also be produced by a "hot dip" method in which a steel plate as a base material is immersed in molten aluminum. m The steel plate material to be formed is immersed in molten aluminum, and mutual diffusion and reaction between the surface of the steel plate material and the molten aluminum occurs, forming an aluminum alloy layer L a Then, when the aluminum is pulled up from the molten aluminum, the alloy layer L a The aluminum layer L is formed by depositing aluminum on the surface of the Al and the aluminum layer L Al The aluminum on the top surface of the ceramic layer L reacts with the surrounding air. c In this case, the base material L is immersed in the molten aluminum to form a thin film of aluminum oxide. mBy immersing all the steel plates, the iron in the steel reacts with the molten aluminum to form the base material L. m The aluminum alloy layer covers the entire surface of the steel plate material as the aluminum alloy layer, and when the aluminum alloy layer is pulled up, the entire surface of the aluminum alloy layer is covered with the aluminum layer L. Al When the aluminum layer reacts with the surrounding air, the entire surface of the aluminum layer is covered with an aluminum oxide layer L c The heat sink 24 can be constructed so that it covers the base material L, and the heat sink 24 can be manufactured efficiently. m The heat is transmitted to the inner lid 26 through the steel plate material, and the aluminum alloy layer L a The heat from the lid heater 31 can be effectively transferred to the inner lid 26 through the lid heater 31 .

[0038] As described above, the rice cooker 100 of this embodiment includes the bottomed cylindrical pot 5, the inner lid 26 that covers the opening of the pot 5, the heat sink 24 that contacts one side of the inner lid 26, which is the surface facing the pot 5, and the lid heater 31 that is disposed on the other side of the heat sink 24, which is the surface facing the outer lid 22, and serves as heating means for heating the inner lid 26 via the heat sink 24. The heat sink 24 is made of a base material L. m and a ceramic layer L located on the surface of the heat sink 24. c and base material L m and ceramic layer L c The aluminum alloy layer L is located between a The configuration includes the following.

[0039] With this configuration, the strength can be significantly improved compared to conventional heat sinks made only of aluminum, and because the heat sink 24 covers most of the underside of the mechanism 71, the strength of the recess 68 in which the mechanism 71 is provided, i.e., the outer lid cover 23 that forms the lower part of the lid 2, is improved, thereby improving the strength of the entire lid 2. Furthermore, since the need for further reinforcement of the lid 2 is reduced, there is less need for lid reinforcing plates 51, 52 that supplement the strength of the lid 2, and the rigidity of the lid reinforcing plates 51, 52 can be lowered, and the weight of the lid 2 can be reduced by reducing or eliminating the lid reinforcing plates 51, 52.

[0040] In addition, the rice cooker 100 of this embodiment has a ceramic layer L c The aluminum alloy layer L may be mainly composed of aluminum oxide (Al2O3), which can enhance the thermal radiation property. a In combination with this, it is possible to provide a heat sink 24 with excellent heat resistance.

[0041] In addition, the rice cooker 100 of this embodiment has an aluminum alloy layer L a However, it may be composed mainly of an alloy of aluminum and iron (Fe-Al), which can improve corrosion resistance and thermal conductivity, and the ceramic layer L c In combination with this, it is possible to provide a heat sink 24 with excellent heat resistance.

[0042] In addition, the rice cooker 100 of this embodiment has an aluminum alloy layer L a is the base material L m The entire surface of the steel sheet is covered with a ceramic layer L c is the aluminum alloy layer L a The ceramic layer L on the surface may be configured to cover the entire surface. c The aluminum alloy layer L in the middle layer has high thermal radiation properties. a In addition to the properties of high corrosion resistance and thermal conductivity due to the m The heat sink 24 made of this steel plate has significantly higher strength than the conventional one made of only aluminum. mThe heat is transmitted to the inner lid 26 through the steel plate material, and the aluminum alloy layer L a The heat from the lid heater 31 can be effectively transferred to the inner lid 26 through the lid heater 31 .

[0043] In the rice cooker 100 of this embodiment, the heat sink 24 is an aluminum-plated steel plate, and the aluminum alloy layer L a is the base material L m The steel plate is immersed in molten aluminum, and the aluminum reacts with the steel plate to produce an alloy of aluminum and iron (Fe-Al), which forms a ceramic layer L. c is the aluminum layer L that adheres to the surface of the steel sheet after immersion. Al The heat sink 24 may be configured so that aluminum oxide (Al2O3) is generated by reacting its surface with air, and can be manufactured efficiently by generating the heat sink 24 using a "hot dip" method.

[0044] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. Furthermore, the numerical values ​​exemplified in the embodiment are merely examples, and may be modified as appropriate depending on the specifications of the rice cooker 100. [Explanation of symbols]

[0045] 5. Hotpot 24 Heat sink 26 Inner lid 31 Lid heater (heating means) L a Aluminum alloy layer L c Ceramic layer L m Base material 100 rice cookers

Claims

1. A cylindrical pot with a bottom, an inner lid that covers the opening of the pot; a heat sink that contacts the inner cover on one side; a heating means disposed on the other surface of the heat sink and configured to heat the inner lid via the heat sink, The heat sink is A steel plate as the base material, a ceramic layer located on the surface of the heat sink; an aluminum alloy layer located between the steel plate and the ceramic layer; A rice cooker comprising:

2. 2. The rice cooker according to claim 1, wherein the ceramic layer is composed mainly of aluminum oxide.

3. 2. The rice cooker according to claim 1, wherein the aluminum alloy layer is mainly composed of an alloy of aluminum and iron.

4. the aluminum alloy layer covers the entire surface of the steel plate, 2. The rice cooker according to claim 1, wherein the ceramic layer covers the entire surface of the aluminum alloy layer.

5. the aluminum alloy layer is produced by immersing the steel sheet in molten aluminum to cause a reaction between the steel sheet and the aluminum, 5. The rice cooker according to claim 1, wherein the ceramic layer is formed by a reaction between the surface of the aluminum and air.

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