JP3275288B2 - Rice cooker and method for producing lower surface member of lid of rice cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice cooker in which an inner lid at a lower portion of a lid is eliminated, and more particularly to a rice cooker in which a lower member of a lid covering an upper opening of a pot is improved and a lid of the rice cooker. The present invention relates to a method for manufacturing a lower surface member.

[0002]

Conventionally, as a rice cooker of this type, for example, Japanese Patent Application Laid-Open No. 7-204086 discloses a so-called rice cooker in which an upper opening of a pot is directly covered by a cover lower plate forming a lower portion of a cover. A structure without an inner lid (without inner lid) has been proposed. The rice cooker with such a structure is easy to use because there is no trouble of attaching and detaching the inner lid, and there is no need to clean the inner lid. On the other hand, a lid that is soiled due to the adhesion of rice (starch-dissolved water) during cooking. It is necessary to wipe the lower surface of the body. For this reason, if the lid is deformed or squeezed when wiping the tongue, it becomes difficult to wipe the lid, so it is necessary to ensure sufficient strength of the lid.

As a method of solving such a problem, there is a method of increasing the material thickness of the lower surface of the lid to improve the strength of the lid. However, in this method, the weight of the entire lid becomes too heavy, and when the lid is opened by a hinge spring such as a torsion coil spring provided in the hinge portion, the lid is automatically opened when the elastic force of the hinge spring is increased. You cannot open it. In addition, since the impact force applied to the hinge portion when the lid is opened increases, the rice cooker body jumps up when the rice cooker body is light, such as when the pot is not housed in the rice cooker body. There is a problem that, for this purpose, there is a problem that it is necessary to separately provide a damper mechanism or the like for suppressing the lid opening operation force in the middle of the lid opening operation.

[0004] As such an improvement measure, as a lower surface member provided on the lid, irregularities are formed by press molding on the surface of a metal plate material having a relatively thin material thickness of about 0.7 mm to 2.0 mm to form a hammer. There is a method of improving strength by work hardening by working. However, in the case of this method, if the upper surface of the lower member also has irregularities, when the upper surface is provided with a lid heater for heating the lower surface of the lid, the adhesion between the lid heater and the upper surface of the lower member is deteriorated, and the efficiency is reduced. There is a problem that the lower surface member cannot be heated well. Further, in the case where the lid heater is a cord-shaped heater, which is covered with an aluminum foil and adhered with an adhesive, there is a problem that the adhesive area is reduced, the adhesiveness is deteriorated, and the heater is easily peeled off.

[0005] Conventionally, the lid is heated at the time of cooking rice, and the cooked food is heated from above by radiation heat from the lower surface of the lid,
The rice cooking method that reduces the moisture at the top not only reduces uneven cooking, but also reduces the adhesion of steam during cooking, so that the soup does not run down along the bottom of the lid when the lid is opened at the end of uneven rice cooking. That is well known. Further, it is also known that the lid is heated at the time of heat retention to prevent the steam of the rice from condensing and adhering to the lower surface of the lid as a soup, so that the amount of the soup is prevented from dropping onto the rice.

[0006] However, if the temperature distribution in the heating of the lid body is uneven, the precious lid heating function conversely increases the temperature difference between the high-temperature part and the low-temperature part, so that the original purpose cannot be sufficiently achieved.

It is also well known that a non-adhesive plastic film such as a fluororesin coat is formed on the lower surface of the lid so that the rice cake does not stick during rice cooking.

However, when a control element such as a triac for controlling the heating of the lid breaks down and the lid is continuously heated, the plastic film melts and peels off, and after repairing the failure, the lower surface of the lid is replaced. There was a problem that it was necessary.

In view of the above problems, the present invention improves the wiping properties of the tongue on the lower surface of the lid and suppresses uneven heating during cooking and keeping the temperature while utilizing the advantage of eliminating the inner lid. The purpose is to provide. Another object of the present invention is to provide a rice cooker that is less damaged when the lid heating device breaks down and has good repairability. Further, the present invention provides a method of manufacturing a lower surface member of a rice cooker capable of manufacturing a lower surface member of a lid that improves the wiping properties of the lower surface of the lid and suppresses uneven heating during cooking and keeping warm. The purpose is to do.

[0010]

According to a first aspect of the present invention, there is provided a rice cooker, wherein a lower surface member of a lid covering an upper opening of a pot is formed of a metal having a partially different material thickness. In addition to being formed of a material, the pot-facing surface of the lower surface member facing the pot and the inner surface facing the inside of the lid are formed in different surface shapes, and the thickness of the material of a portion that is easily weakened in strength Can be increased.

Further, in the rice cooker according to the invention of claim 2, in addition to the configuration of claim 1, a plurality of irregularities are formed on the pot-facing surface of the lower surface member, and the rice cooker corresponds to the irregularities. By providing the lid heating device on the inner surface of the lower surface member, the surface area of the pot facing surface can be increased and the pot facing surface can be uniformly heated when the lid is heated.

Further, in the rice cooker according to the third aspect of the present invention, in addition to the configuration of the first aspect, a non-adhesive plastic film is provided on the pot-facing surface, and a lid heating device is provided on the inner surface. The configuration is such that the melting temperature of the plastic film is higher than the temperature of the lower surface member when the lower surface member is continuously heated by the lid heating device. Even so, peeling of the plastic film can be prevented.

According to a fourth aspect of the present invention, in the method of manufacturing the lower surface member of the lid of the rice cooker, the lower surface member of the lid covering the upper opening of the pot is formed of a metal material having a partially different material thickness. A method of manufacturing a lower surface member of a lid of a rice cooker,
Since the molten metal is solidified and molded in a mold having a predetermined shape, it is possible to manufacture a metal lower surface member having a partially different predetermined material thickness.

Further, in the method of manufacturing the lower surface member of the lid of the rice cooker according to the present invention, the lower surface member of the lid covering the upper opening of the pot is formed of a metal material having a partially different material thickness. A method for manufacturing a lower surface member of a lid of a rice cooker, wherein a uniform plate-shaped metal material is formed by press forming, so that a predetermined material thickness is partially changed by press working. Can be manufactured.

[0015]

Hereinafter, an embodiment of the present invention will be described.
This will be described with reference to FIGS. Reference numeral 1 denotes a container body, which is a bottomed cylindrical inner frame 2 having an open upper surface, an outer frame 3 having the inner frame 2 therein and forming an outer shell of the container body 1,
The bottom plate 4 covers the bottom side of the outer frame 3. The inner frame 2 serving as a container housing portion is made of PET resin containing glass fiber, and is formed in a shape substantially similar to the outer surface shape of the pot 5 detachably housed in the inner frame 2.

The shape of the pot 5 for accommodating rice or water to be cooked is formed in a bottomed cylindrical shape having an open upper surface.
At the top of the outer surface of the pot 5, a flange-shaped handle 6 projecting horizontally outward is formed. The pan 5 is supported in a hung state by the handle portion 6 being placed on the upper end surface of the outer frame 3, and between the inner frame 2 and the pan 5 housed therein.
Except for the handle 6, a predetermined gap 7 of 1 to 4 mm is formed. The pot 5 is provided with a pot main body 8 mainly composed of, for example, an A3004 type aluminum material having excellent heat conductivity and corrosion resistance, and is provided from the outer bottom surface to the lower side of the pot main body 8. The heat generating layer 9 is made of a magnetic metal material.

Further, the overall shape of the pot 5 will be described in detail. Pot 5
The outer surface of the curve is connected to the lowermost portion 11 of the outer bottom surface of the pot 5 with a decreasing rate of the diameter increasing as the height decreases from a height h approximately at the middle of the total height H or about 1/3 of the total height H. When the pot 5 is placed on a flat table surface or the like, the lowermost portion 11 of the pot 5 comes into contact with the table surface or the like. The outermost peripheral portion 12 of the inner bottom surface facing the outermost peripheral portion of the lowermost portion 11 of the pan 5 has a diameter A2 of 25% to 75% (1/1) of the diameter A1 of the upper opening 13 of the pan 5.
4 to 3/4). The inner surface of the pan 5 has a vertical cross-sectional shape substantially along the outer surface of the pan 5, and faces the lowermost portion 11 from a side position approximately at the middle of the total height H or about １ ／ of the total height H. It is formed in the shape of a curved surface over the bottom surface to be formed. Here, the side surface refers to a region from the upper surface opening 13 including the handle portion 6 to the outermost peripheral portion of the lowermost portion 11 (a portion located at the outermost peripheral portion 12) in contact with a table surface or the like. The curved surface portion 14 having the above-mentioned curved inner surface is formed from to the bottom surface. The heat generating layer 9, which is a heat generating portion of the pot 5, is formed on the outer surface of the curved portion 14 of the pot 5.

Reference numeral 21 denotes a heating coil provided outside the inner frame 2 and corresponding to a pot heating device for causing the heating layer 9 of the pot 5 to generate heat by electromagnetic induction. The heating coil 21 is helically wound and fixed on the outer surface of the inner frame 2 at a position facing the heat generating layer 9 on the curved surface portion 14 from the lower side surface to the bottom surface of the pot 5. The heating coil 21 may be provided in a portion other than this portion. However, the heating coil 21 is placed at a position facing the curved surface portion 14 of the pot 5 at least so that heat convection of water in the pot 5 is easily generated at the time of cooking rice. Preferably, 21 is provided. On the outside of the heating coil 21, a coil cover 22 having an insulating property in which a high magnetic permeability material powder mainly composed of iron oxide or the like is mixed with a plastic material is provided.
Is fixed to a cylindrical portion 22A projecting upward at the center of the heat generating layer 9 to prevent the leakage of magnetic flux and efficiently heat the heat generating layer 9 by electromagnetic induction heating. By forming the coil cover 22 with the insulating plastic mixed with the material powder having a high magnetic permeability in this way, the structure is simplified because both the fixing of the heating coil 21 and the prevention of magnetic flux leakage are performed by one functional component. It has a configuration. Reference numeral 23 denotes a pot temperature sensor provided near the heating layer 9 of the pot 5 and provided with a negative temperature coefficient thermistor therein. Reference numeral 24 denotes a pot located near the heating layer 9 and the heating coil 21. This is a thermal fuse provided on the outer surface of the frame 2.

Reference numeral 26 denotes a heating board provided with an inverter circuit component 27 for supplying a predetermined high-frequency current to the heating coil 21. The heating substrate 26 is disposed between the bottom plate 4 at the bottom of the container body 1 and the support 28 together with the cooling fan 30 provided with the motor 29 by the support 28 provided inside the container body 1. An intake port 31 is provided at the bottom of the bottom plate 4 facing the cooling fan 30, and an exhaust port 32 is provided at a side surface of the bottom plate 4 facing one side of the heating substrate 26. Support 28
Is provided upright on one side of the heating substrate 26. Between the support 28 and the front surface of the main body 1, an LCD 33 and an LED forming an operation panel 33 as display operation means are provided.
A display operation component 36 having 34 and various switches 35;
A power supply circuit component 37 other than the inverter circuit component 27 is
It is provided in a state of being mounted on. When the cooling fan 30 is rotated by energizing the motor 29, the air taken in from the intake port 31 is sent out from the heating substrate 26 to the exhaust port 32 through the substrate 38, and the air flows between the support 28 and the bottom plate 4. Each part in the space surrounded by is forcibly cooled. 39 is a power cord 40 provided on the lower rear side of the outer frame 3.
Is a code reel that winds up.

Reference numeral 41 denotes a lid that covers the upper opening 13 of the pot 5 so that it can be opened and closed. The lid 41 is attached to the outer lid 42, an outer lid cover 43 provided along the lower outer periphery of the outer lid 42, and forming a space below the outer lid 42, and a lower surface of the lid 41. A lid lower plate 44 made of aluminum material directly covers the upper opening 13 of the pot 5 as a member. The outer lid 42 is formed into a three-dimensional appearance with excellent design by injection molding a plastic such as polypropylene, and can be freely colored, so that the degree of freedom in design can be improved. . Reference numeral 45 denotes a lid packing held between the outer lid cover 43 and the lid lower surface plate 44, and the lower end of the lid packing 45 comes into close contact with the handle 6 of the pan 5 when the lid 41 is closed. A hinge shaft 46 is rotatably supported on an upper portion of the rear surface of the container body 1, while a lid 41 opposite to the hinge shaft 46 is provided.
Alternatively, a clamp button 46A for locking the lid 41 and the container body 1 is provided on the front side of the container body 1. Although not shown, an elastic member such as a torsion coil spring that urges the lid 41 in the direction of always opening is provided inside the hinge shaft 46, and by pressing the clamp button 46A, The lid 41 can be opened with the hinge shaft 46 as the center of rotation.

A concave portion 47 and a convex portion 47A are provided on a pot facing surface 44A of the cover lower plate 44 facing the pot 5, and the strength is improved by work hardening. If the depth of the concave portion 47 is large, the effect of improving the strength is high, but the surface may be difficult to wipe off. Therefore, it is preferable that the depth B is formed within about 1 mm. The shapes of the concave portion 47 and the convex portion 47A are not particularly limited, and are formed in consideration of design properties such as a circle, an ellipse, a triangle, and a turtle pattern. On the other hand, the inner surface 44B of the lid lower surface plate 44 facing the inside of the lid 41 has a flat shape or a protruding shape with a low projecting height that is small enough to enable bonding of a lid heater described later.

Next, a recess 47 is formed in the pot facing surface 44A of the lid lower plate 44.
A method of manufacturing the lid lower plate 44 in which the convex portion 47A is provided and the inner surface 44B is made flat or almost flat so that the pot facing surface 44A and the inner surface 44B have different surface shapes will be described. The first manufacturing method is based on a melt forging method.
In this melt forging method, aluminum heated in a molten state is poured into a lower mold, tightened by an upper mold, pressurized and solidified from above, molded and formed, and a recess 47 and the like are formed by a mold composed of a lower mold and an upper mold. A lid lower plate 44 having a predetermined shape is formed. The second manufacturing method is based on an aluminum die casting method. In this aluminum die casting method, a molten aluminum is poured into an upper and lower mold, solidified and formed, and a lower surface plate 44 having a predetermined shape in which a concave portion 47 and the like are formed by a metal mold is formed. According to such a melt-forging method or an aluminum die-casting method, the thickness C1 of the material on the outer peripheral side of the lid lower surface plate 44 is formed to be as thick as about 3 to 6 mm, and the thickness C2 on the center side is changed to the thickness C1 of the material. It can be formed to a thinner thickness of about 1.5 to 3 mm, and can be formed into a plate shape having a non-similar shape and a non-uniform material thickness between the pot facing surface 44A and the inner surface 44B. Further, a third manufacturing method is a press molding manufacturing method. In this press molding method, as shown in FIG. 3, a concave portion 47 is stamped and formed in an aluminum plate having a thickness of about 1 to 3 mm by pressing, and then press molded into a predetermined shape. Indicates that a concave mark is formed only on the surface corresponding to the pot facing surface 44A.

A lid lower plate formed by such a manufacturing method
44 is subjected to a corrosion prevention treatment by alumite treatment, and then the blasted pot facing surface 44A is coated with PFA resin and dried, and then coated with PFA resin again, and then coated with 2 coats and 2 bake fluorine resin. Forming a two-layer plastic film 53 having a melting temperature of about 240 degrees Celsius.

An inner surface 44B of the lid lower plate 44 has a lid lower plate 44
A cord heater 48 as a lid heating means, which is a lid heater for heating the heater, is provided at a position corresponding to the concave portion 47 and the convex portion 47A. This cord heater 48 is about 20 to 100 W,
The surface temperature of the pot-facing surface 44A is configured to be 200 degrees Celsius or less in a state where the ambient room temperature is 35 degrees Celsius and the voltage is applied continuously at 110 V. The cord heater 48 is electrically connected to a side heater 49 such as a cord heater for keeping the inner frame 2 warm by a parallel circuit. And code heater 48
The side heater 49 and the side heater 49 are connected by a series circuit to a power cutoff control element such as a triac which is a control means of a lid heating device (not shown). Further, on the inner surface 44B side of the lid lower surface plate 44, a lid temperature sensor 50 composed of a negative characteristic thermistor for detecting the temperature of the lower surface of the lid 41 is provided, and a predetermined temperature is determined according to the temperature detected by the lid temperature sensor 50. The temperature of the lid lower plate 44 is controlled to a temperature. Code heater 48 and lid temperature sensor 50
Are covered with an aluminum foil 51, and the upper surface of the aluminum foil 51 is provided with a heat insulating plate 52 along with an outer lid cover 43 and a lid lower plate 44 while forming a predetermined space.
Is mounted and fixed. 50A is a sensor holder for holding the lid temperature sensor 50 on the upper surface of the lid lower plate 44. Incidentally, the heating of the cord heater 48 and the side heater 49 may be configured to heat the lid lower plate 44 during rice cooking and heat keeping by controlling the predetermined energizing time.

Reference numeral 61 denotes a steam entry hole provided substantially at the center of the lid lower plate 44 and the pan 5.
The steam enters the steam port 62 from 61. Steam vent
The structure around 62 is described in detail.
A recess 63 is provided for mounting the
A steam port cover 65 having a steam discharge port 64 formed on the upper surface exposed to the outside of the lid 41, and a bottomed cylindrical bucket 66 provided inside the steam port cover 65 so as to be vertically movable. Assembled and configured. The bucket 66 is made of a metal material made of aluminum or stainless steel, or a plastic material such as polypropylene, and a bulging portion 67 corresponding to the bottom of the steam port 62 formed below the bucket 66 has a steam port cover 65.
Are provided so as to protrude from the lower surface opening 68. On the outer upper part of the steam port cover 65, a projection 70 is formed to be locked to the locked piece 69 of the outer lid 42. The engagement and disengagement of the locked piece 69 and the projection 70 The steam port 62 can be further attached and detached.

Reference numeral 71 denotes a steam port packing for sealing between the lower end of the recess 63 and the lid lower plate 44. This steam port packing 71
Is for preventing the invasion of steam into the lid 41, and when the steam port 62 is mounted in the recess 63, the steam port cover 65
The bent part 72 formed at the lower part of the outer periphery of the
A configuration in which the bottom surface of the bulging portion 67 of the bucket 66 is placed on the upper surface of the lid lower plate 44 exposed to the inner bottom surface of the concave portion 63 and closes the vapor intrusion hole 61 of the lid lower plate 44 while being in close contact with the inner end of the bucket 71. It has become. In addition, the bucket 66
A partition plate 74 having a plurality of communication holes 73 communicating the inside and the outside of the device is provided. At the center of the bulging portion 67 of the bucket 66, there is provided a return hole 75 through which the lumps collected inside the bucket 66 during rice cooking flow. The return hole 75 is a check valve made of an elastic member such as silicone rubber. It is in a state of being closed by the tongue piece 77 of 76. Therefore, the steam generated during the rice cooking enters through the steam entry hole 61 and abuts against the bottom surface of the bucket 66,
At this time, the pressure of the steam pushes the bucket 66 upward from the lid lower surface plate 44 and passes through a steam passage hole 78 formed between the outer surface of the bucket 66 and the inner surface of the steam port cover 65 to pass through the steam port cover. The steam is discharged to the outside of the lid 41 from the steam discharge port 64 on the upper surface of the cap 65. Thereafter, when the rice cooking is completed, the heating is stopped, and the process shifts to spots, the inside of the pot 5 becomes negative pressure, so that the check valve 76 moves toward the pot 5 and forms a lower portion of the check valve 76. From between the tongue piece 77 and the return hole 74, the bucket 66
The tonnage that has accumulated inside the container returns to the pot 5 side.

When the temperature is kept warm, the pressure of the steam in the pot 5 decreases, and the bucket 66 is moved by its own weight.
It is placed on the upper surface of 44 and closes the vapor entry hole 61 of the lid lower plate 44. The cord heater 48 is disposed so as to surround the steam port 62 around the steam inlet 61, that is, within a range of about 30 mm around the steam port packing 71. When the lower plate 44 is heated, the vapor intrusion holes 61 near the lower plate 44 are heated, and
The bucket 66 in contact with the lid lower plate 44 is heated by heat conduction.

In the above configuration, when a high-frequency current is supplied to the heating coil 21 from the inverter circuit mounted on the heating board 26, an alternating magnetic field is generated in the heating coil 21 and the heating layer of the pot 5 located in the magnetic field. An eddy current is generated in the pan 9 and the eddy current is converted into Joule heat, so that the heating layer 9 generates heat and heats the cooked rice inside the pan 5.

As described above, the jar-type rice cooker of the present embodiment has a structure in which the upper opening 13 of the pot 5 is covered by the lid lower surface plate 44 of the lid 41 instead of the inner lid. Since there is no trouble of attaching and detaching the inner lid, and there is no need to clean the inner lid, it is practically convenient. Further, since the thickness of the material of the lid lower surface plate 44 is partially changed so that the thickness C1 of the material on the outer peripheral side is larger than the thickness C2 of the central portion, the lid lower surface plate 44 tends to be weak in strength. Can be improved on the outer peripheral side. Further, by providing a plurality of concave portions 47 and convex portions 47A on the pot facing surface 44A, work hardening occurs and strength can be further improved. By improving the strength of the lid lower plate 44 in this way, only the portion of the lid lower plate 44 necessary for ensuring the strength can be made of a thicker material, so that the strength is improved and the weight is increased. Can be reduced. As a result, when wiping the bean on the pot facing surface 44A, the lid lower plate
There is no risk that the 44 will be deformed, and it can be wiped with peace of mind, improving cleanability. In addition, since the weight is reduced, it is not necessary to excessively increase the elastic force of an elastic member such as a torsion coil spring that urges the lid 41 in the direction in which the lid 41 is always opened. The impact force to be applied is reduced, and it is possible to eliminate the possibility that the container body 1 jumps backward when the weight of the container body 1 is light, such as when the pot 5 is not accommodated in the container body 1. Further, unlike the surface shape of the pot-facing surface 44A, by making the inner surface 44B flat or almost flat without any protrusions, the adhesion between the inner surface 44B and the code heater 48 can be improved, and the lid lower plate 44 can be efficiently removed. Can be heated. In particular, when the lid heating means is a cord heater 48, and the cord heater 48 is covered with an aluminum foil 51 and adhered with an adhesive, it is possible to secure an adhesion area and to prevent peeling.

Further, a cord heater 48 as a lid heating means is provided.
Are provided on the inner surface 44B corresponding to the concave portion 47 and the convex portion 47A, so that the pot facing surface 44 thermally corresponding to the cord heater 48 is provided.
The surface area of A increases. For this reason, the local heating of the pot facing surface 44A is suppressed, the temperature unevenness of the lid heating is reduced, the temperature difference between the high temperature part and the low temperature part is eliminated, and the uniform heating of the upper space of the pot 5 during the rice cooking reduces uneven cooking. In addition to the reduction, it is possible to reliably prevent dew condensation on the lid lower plate 44 during the heat retention.

Further, the plastic film 53 provided on the pot facing surface 44A of the lid lower plate 44 is made of a fluorine resin such as PFA resin so that the rice is not stuck during rice cooking. Since the temperature of the lid lower surface plate 44 is about 240 degrees Celsius, which is higher than the temperature of the lid lower plate 44 when the heating is performed, for example, when a control element such as a triac for controlling the lid heating has failed, or when the lid temperature sensor
Even if the lid is continuously heated by the code heater 48, for example, when the wire 50 is disconnected and cannot be detected normally, the plastic coating 53 is prevented from melting and peeling. For this reason, the inconvenience that the cover lower plate 44 must be replaced at the same time after repairing the cause of the failure is eliminated, and the repairability can be improved.

Also, by manufacturing the lid lower plate 44 by the above-described melt forging method or an aluminum die casting method in which molten aluminum is injected and formed, a portion on the outer peripheral side and the like necessary for ensuring strength is thickened. For example, the lid lower plate 44 can be formed freely and easily, and can improve the strength and reduce the weight as described above.

Further, as shown in FIG. 3, a concave portion 47 is formed on one surface of a flat aluminum plate by press working to form a pot facing surface 44A, while a lid is formed by a press forming process for forming an inner surface 44B flat. By manufacturing the lower plate 44, it is possible to manufacture the lid lower plate 44, which can improve strength by work hardening and can improve strength and reduce weight as described above without special equipment.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, although an electromagnetic induction heating type rice cooker is shown in the embodiment, another heating type rice cooker in which a pan is heated by a sheath heater or the like may be used.

[0035]

According to the rice cooker of the first aspect of the present invention, the lower surface member of the lid covering the upper opening of the pan is formed of a metal material having a partially different material thickness, and the lower surface member has the pot. By forming the pot-facing surface and the inner surface facing the inside of the lid different from each other, the strength of the lower surface member of the lid is improved while taking advantage of eliminating the inner lid. If it is safe, it can be wiped off and the cleaning property can be improved. In addition, the weight of the lower surface member, and thus the lid, is reduced so that it does not become excessively heavy, whereby the lifting of the container body when the lid is opened is suppressed, and the usability can be improved.

In the rice cooker according to the second aspect of the present invention, in addition to the configuration of the first aspect, a plurality of uneven portions are formed on the pot-facing surface of the lower surface member, and the lower surface corresponds to the uneven portions. By providing a lid heating device on the inner surface of the member, not only the function and effect of claim 1, but also the surface area of the pot facing surface can be increased, and uneven heating of the pot facing surface by the lid heating device can be reduced, and during cooking rice The upper space of the pan can be uniformly heated, and uneven cooking can be reduced. In addition, it is possible to prevent dew condensation on the lower surface member during the heat retention, thereby preventing the soup from dropping on rice.

Further, in the rice cooker according to the third aspect of the present invention, in addition to the configuration of the first aspect, a non-adhesive plastic film is provided on the pot-facing surface, and a lid heating device is provided on the inner surface. 2. The lid according to claim 1, wherein the melting temperature of the plastic film is higher than the temperature of the lower surface member when the lower surface member is continuously heated by the lid heating device. Even if there is a failure in the control means of the heating device, the plastic film does not peel off, so that repairability can be improved.

According to a fourth aspect of the present invention, there is provided a method for manufacturing a lower surface member of a rice cooker, wherein the lower surface member of the lid covering the upper opening of the pot is formed of a metal material having a partially different material thickness. A method of manufacturing a lower surface member of a rice cooker lid, wherein a lower surface member capable of freely improving the strength of a predetermined portion is configured by solidifying and molding a molten metal in a mold having a predetermined shape. Can be manufactured.

Further, in the method of manufacturing a rice cooker lid lower member according to the invention of claim 5, the lid lower surface member covering the upper opening of the pot is formed of a metal material having a partially different material thickness. This is a method of manufacturing the lower surface member of the lid of a rice cooker, and is configured to press-mold a uniform plate-shaped metal material, so that the strength can be improved by work hardening and even without special equipment. Can be manufactured.

[Brief description of the drawings]

FIG. 1 is an overall sectional view of a rice cooker showing one embodiment of the present invention.

FIG. 2 is a sectional view of a lid lower plate showing one embodiment of the present invention.

FIG. 3 is a sectional view of a cover lower plate showing another embodiment of the present invention.

[Explanation of symbols]

 5 Pot 13 Upper opening 41 Lid 44 Lower lid plate (lower member) 44A Pot facing surface 44B Inner surface 47 Depression 47A Convex portion 48 Code heater (lid heating means) 53 Plastic coating

Claims (5)

(57) [Claims] 1. A lower surface member of a lid that covers an upper opening of a pan is formed of a metal material having a partially different material thickness, and a pot-facing surface of the lower surface member facing the pan and the lid. A rice cooker characterized by having a different surface shape from an inner surface facing the inside of the rice cooker. 2. A method according to claim 1, wherein a plurality of uneven portions are formed on the pot-facing surface of the lower surface member, and a lid heating device is provided on an inner surface of the lower surface member corresponding to the uneven portions. The described rice cooker. 3. A non-adhesive plastic film is provided on the pot-facing surface, a lid heating device is provided on the inner surface, and the lower surface member is continuously heated by the lid heating device. 2. The rice cooker according to claim 1, wherein a melting temperature of the plastic film is set higher than a temperature of the rice cooker. 4. A method for manufacturing a lower surface member of a rice cooker lid, wherein the lower surface member of the lid covering the upper opening of the pot is formed of a metal material having a partially different material thickness, the method comprising: And a method for manufacturing a lower surface member of a lid of a rice cooker, wherein the lower surface member is formed by solidifying in a mold having a predetermined shape. 5. A method for manufacturing a lower surface member of a rice cooker lid, wherein the lower surface member of the lid covering the upper opening of the pot is formed of a metal material having a partially different material thickness. A method for manufacturing a lower surface member of a lid of a rice cooker, wherein a plate-shaped metal material is press-formed.