JP4992307B2 - Electric rice cooker - Google Patents

Description

  In the present invention, a heating coil is arranged between the bottom portions of the inner and outer cases of the main body, and a heating element is provided at a portion facing the heating coil of the pan housed in the main body so that induction heat is generated by an alternating magnetic field from the heating coil. Further, the present invention relates to an electric rice cooker in which the body portion of the resin-made interior case is a metal body frame.

Thus, the electric rice cooker with the resin-made interior case which used the trunk | drum as a metal trunk | drum frame is already made (for example, refer patent document 1, 2). In Patent Document 1, the bottom of the hook accommodated in the main body is induction-heated by a heating coil disposed between the bottoms of the inner and outer cases of the main body, and is wound around the metal body frame of the inner case body. The heater is indirectly heated from the side portion through the metal body frame by the heater. Patent Document 2 discloses a heating coil in which an inner pot in which ceramic or ceramic and glass are mixed is housed in a main body, a magnetic heating element is provided on the outer surface of the bottom of the inner pot, and provided between the bottoms of the inner and outer cases of the main body. Inductive heat is generated by magnetic coupling with an alternating magnetic field from the inside, and the pan is indirectly heated from the side through the metal body frame by a heater wound around the metal body frame of the interior case body. I am doing so.
JP 2003-180513 A JP-A-2005-413

  By the way, rice cooking is an important condition for cooking rice that is particularly delicious with uniform heating. In addition, if there is a partial temperature difference when the cooked rice is kept warm, condensation occurs, causing the rice to become sticky or whiten, so uniform heating is important.

  Based on this point of view, the heat generator on the inner surface of earthenware pots is heated as we research and practice the electric rice cooker using non-metal thick pots such as earthenware pots that are easily heated. Although the efficiency is good, uniform heating is difficult, and the heating element on the outer surface of the clay pot is less likely to utilize high-power heating from the bottom for cooking rice because the thermal conductivity of the clay pot is as small as 1/200 of aluminum. When the output is increased by that amount, it has been found that local overheating on the pan side and abnormal heating of the heating coil itself due to this overheating are caused.

  For these reasons, the present inventor has determined that it is advantageous to increase heating with a heating source such as a heater provided on a metal barrel frame in order to use clay pots in an electric rice cooker. It becomes necessary to expand the main body heating coil side with the metal body frame. However, the expansion to the dark heating coil side adversely affects the magnetic action of induction heat generation from the heating coil to the heating element facing the heating coil, and does not lead to stable and good rice cooking.

  Therefore, the object of the present invention is to improve the heating to the side of the pan from the heating source provided on the metal barrel frame of the interior case in the main body without affecting the induction heating action from the heating coil to the heating element, and is stable and good. It is to provide an electric rice cooker that can cook rice.

To achieve the above object, an electric rice cooker of the present invention, by arranging the heating coil between the bottom of the body of the interior and exterior case, the heating element to the portion facing the heating coil of the soil pot accommodated in the main body In order to generate induction heat by an alternating magnetic field from the heating coil, the body part of the resin interior case is used as a metal body frame, and a side heating source is arranged around the outside, and this metal body frame is made nonmagnetic. avoid magnetic action between the alternating magnetic field around the heating coil by a metal, soil pot from the inner surface side in order to assist heat transfer to the pot inward from the heating element of the outer surface to secure drop strength On the outer surface, the lower half is thinner than the upper half, and the gap between the heating coil and the interior case located between the heating coil is larger than the upper half in the area corresponding to the lower half, and air that dissipates the heat radiated from the heating element Forming a gap, the clay pot on its molding Supported on the bottom of the interior casing at the outer peripheral leg provided in order to absorb the error, it is characterized by suppressing the fluctuation of the distance between the heating element and the outer case.

Electric cooker having such a configuration, to be the side heating source provided in the metal barrel portion frame of the interior casing of the body housing the soil pot pot sides to heat through the metal barrel frame, When the metal body frame is made of various non-magnetic metals such as Fe, copper and aluminum, the magnetic field can be extended not only to the vicinity of the magnetic field around the heating coil between the bottoms of the inner and outer cases. Even if a metal body frame enters the zone, it is non-magnetic metal, so it generates little heat and has little energy loss and no influence on the surroundings. It contains mainly Co and Ni and their alloys. It is a so-called non-magnetic material that does not contain a ferromagnetic material, and its remanent magnetization is negligible compared to ferromagnetic metals, and it inhibits or changes the induction heating action from the heating coil to the opposing heating element with the interior case in between. Never expanded The heating of the soil pot extended to thin-walled lower half side of the upper half portion only, the outer casing in the cooking time around the while promoting Atsushi Nobori of the thin-walled lower half portion than the upper half of the soil pot It is easy to effectively assist heating from the thin lower half portion that is easy to dissipate heat based on the environment that encourages heat dissipation from the heat generating element in the air gap that is larger than the upper part between the two. In addition, non-metal pans include a heating element and a heating coil at the bottom of the pan by supporting it on the bottom of the interior case with the legs of the bottom, regarding the size and shape, especially the height dimensions that are difficult to stabilize. Stabilizes the distance from the inner case and the air gap width without the influence of pan molding size variation, and effectively uses the heat generated by the heating element to the inside of the pot using the air gap and the air gap from the heating element. And the thermal safety of the interior case side using heat-resistant plates can be ensured as designed.

  A plurality of side heating sources are provided above and below, and when the lowest heating source is located in the vicinity of the heating coil, in addition to the metal barrel frame, the lowest heating source also extends to the magnetic field around the heating coil. Because it is a heater that uses Joule heat, it generates heat even in the eddy current generated by the magnetic field around the heating coil. Heating function can be enhanced.

  Further objects and features of the present invention will become apparent from the following detailed description and drawings. Each feature of the present invention can be used alone or in combination in various combinations as much as possible.

According to the electric rice cooker of the present invention, to be a heat source in a metal barrel frame of the interior casing provided in the body housing the soil pot pot sides to heat through the metal barrel frame, made of metal Even if the body frame is made of non-magnetic metal and is close to the magnetic field around the heating coil, the non-metallic body frame energy loss and influence on the surroundings are extremely small even if it is expanded to enter the magnetic field area. in addition, without or alter or inhibit the induction heating effect between the heating coil across the interior case with negligible residual magnetization and the heating element, the upper half of the heating of the soil pot in proportion to the expansion extended to thin-walled lower half side of the parts, greater than the upper between the outer casing at the cooking time around the while promoting Atsushi Nobori of the thin-walled lower half portion than the upper half of the soil pot easily radiated to the group environment to Kagora heat radiation from a heating element in the air gap as a gap Easily effectively assist the heat from the walled lower half, the heating characteristic is improved without problems of localized overheating due to the heating coil, good cooking is realized by low soil pot thermal conductivity. In addition, non-metal pans include a heating element and a heating coil at the bottom of the pan by supporting it on the bottom of the interior case with the legs of the bottom, regarding the size and shape, especially the height dimensions that are difficult to stabilize. Stabilizes the distance from the inner case and the air gap width without the influence of pan molding size variation, and effectively uses the heat generated by the heating element to the inside of the pot using the air gap and the air gap from the heating element. And the thermal safety of the interior case side using heat-resistant plates can be ensured as designed.

  Even if the lowest one of the plurality of side heating sources is located near the heating coil and reaches the magnetic field area around the heating coil, heat is generated, and there is no influence of the presence of the metal barrel frame. The heating function to the side of the pan is enhanced, and it is effective for cooking rice.

  Hereinafter, embodiments of the electric rice cooker according to the present invention will be described in detail with reference to FIGS.

  As shown in FIG. 1 and FIG. 2, the electric rice cooker according to the present embodiment is mainly a non-metallic pot 1 such as a clay pot, a main body 2 that can be attached and detached, and a main body 2 and a pan 1. And a lid heating source 4 for heating from the bottom of the pan 1, a side heating source 5 for heating from the side of the pan 1, and a lid heating source 6 for heating from the lid 3. It has a basic configuration. The main body 2 is provided with a heating coil 4a of the bottom heating source 4 between the inner and outer cases 11 and 12, and a heating element 4b that is inductively heated by an alternating magnetic field from the heating coil 4a is provided on the outer surface of the bottom of the pan 1 opposite to the heating coil 4a. It is provided. The side heating source 5 is a heater 5a wound around the outer periphery of a metal body frame 11a sandwiched between a resin lower frame 11b and an upper frame 11c in the interior case 11. However, the side heating source 5 can also be a combination of a heating coil and a heating element (not shown), and the metal body frame 11a is made of metal regardless of the type of the heating source, so that a nonmetal such as an earthenware pot is used. Although adopting the detachable pan 1 made of resin, it is possible to deal with the case where the resin is easily damaged or easily damaged by contact with or contact with the pan 1. The lid heating source 6 is a heater 6a wired and attached to the upper surface of a metal heat radiating plate 3c fitted to a resin lower plate 3b combined with a resin upper plate 3a of the lid 3. The heat radiating plate 3c has a size corresponding to the opening of the pan 1, and heats the rice in the pan 1 from above the metal inner lid 7 that closes the opening of the pan 1, and mainly heats the side. In cooperation with 5, keep warm while preventing condensation due to temperature difference. The bottom heating source 4 can be used in combination with the heat insulation of the rice. In particular, the bottom heating source 4 is divided into a central part of the bottom of the pan 1 and an outer peripheral part that rises, for example, in the shape of a round, to the bottom part of the pan. The heating coil 4a2 and the heating element 4b2 are separated. However, the heating coils 4a1 and 4a2 are configured to perform the same energization control as a configuration in which one wire is wound in two places. However, the present invention is not limited to this, and individual energization control can be performed by configuring individual lines.

  As shown in FIG. 1, a power source / drive substrate 111 for driving the bottom heating source 4, the side heat source 5, and the lid heating source 6, and a control for performing rice cooking and cooking in a set mode through the power source / drive substrate 111. The substrate 112 is arranged in a large space formed between the front portions of the inner and outer cases 11 and 12 of the main body 2 and cooperates with the heat sink 13a by the fan 13 to cool a heat generating element such as an IGBT. On the upper surface of the wide front part of the main body 2, there is provided an operation panel 14 for setting various modes, starting rice cooking and cooking, selecting and stopping heat insulation, and an operation board 18 on the inside thereof. It corresponds to various operations on the operation panel 14 and can display the operation state and the operation state. A take-up reel 115 for the power connection cord is accommodated between the rear portions of the main body 2 as a slightly larger space than between the side portions. The lower frame 11b and the upper frame 11c of the interior case 11 of the main body 2 are made of resin so that the lower frame 11b satisfies the magnetic permeability so as not to disturb the electromagnetic action on the heating elements 4b1, 4b2 by the heating coils 4a1, 4a2. Yes. The outer case 12 of the main body 2 is connected to the upper end of the peripheral wall of the resin bottom member 12a by forcibly fitting the lower end edge winding portion of the metal barrel portion 12b, and the upper end of the barrel portion 12b and the upper frame 11c of the interior case 11 are connected. The upper end is connected by a shoulder member 12c made of synthetic resin. The heating coils 4a1, 4a2 are placed on and supported by a resin coil base 15, and ferrite 16 extending radially below the coil base 15 is supported by a resin support base 17, and the heating coils 4a1, 4a2 are provided. The magnetic field generated by is strengthened and stabilized.

  As shown in FIG. 1, the lid 3 is pivotally supported so that it can be opened and closed by a rear bearing portion 2d of the main body 2 and a shaft 21, and is urged in the opening direction by a spring 22, and the sliding contact between the spring 22 and the rear bearing portion 2d. The lid 3 opens slowly due to resistance caused by the above. The front portion of the lid 3 is locked at a closed position by a lock lever 23 provided on the side of the main body 2 so as to be pivotally supported by the shaft 124, so that the lock is released by the unlocking operation of the lock lever 23 and is opened by the spring 22. I have to. In such a closed state of the lid 3, the seal packing 24 sandwiched between the lower plate 3 b and the heat radiating plate 3 c of the lid 3 is pressed against the outer peripheral frame 7 a of the inner lid 7 as shown in FIGS. 1 and 2. In this state, the inner lid 7 is pressed against the horizontal lip of the pan 1 from above with a seal packing 25 provided between the outer peripheral frame 7a, the pan 1 is closed, and rice is cooked or kept warm. Become. In such a closed state, the inner lid 7 has holes (not shown) in the high and low positions, and escapes steam during cooking, or causes the steam that escapes from the inner lid 7 to accompany the escaped steam. It can be returned to the pot 1. Further, a steam pipe 27 is inserted into the hole 26 provided in the center of the lid 3 from below and is held by a seal packing 28 on the inner periphery of the hole 26 so that it can be attached and detached for disassembly and cleaning. The steam pipe 27 has a steam passage 29 having a ball-like check valve 29a, and discharges the steam that has flowed out of the inner lid 7 to the outside of the lid 3 only when the valve pressure of the check valve 29a is exceeded. While the gas-liquid separated rice bowl is returned to the inner lid 7, it is returned to the pot 1.

  Here, the pan 1 may be a non-metallic one, which may be mainly made by firing porcelain clay, but may also include various known ones including ceramics. The heating elements 4b1 and 4b2 of the bottom heating source 4 are conductive layers that generate heat by generating eddy currents by alternating magnetic fields from the heating coils 4a1 and 4a2, and are made of a silver paste of about 10 to several tens μm provided on the outer surface of the pan 1. An application layer by printing or the like, a laminated layer of silver foil, or a silver vapor deposition layer may be used. However, the conductive material and the layer formation method can be freely selected. The heater 5a of the side heating source 5 is equipped by being sandwiched between the press plate 5c on the outer surface of a metal barrel frame 11a which is a heat radiating plate such as aluminum, a steel plate, and stainless steel facing the side of the pan 1. Although mainly used for heat insulation, the lower part of the heater 5a is particularly suitable for cooking rice. For these reasons, the uppermost one of the quadruple heaters 5a has an energization capacity equivalent to 20W, the lower one has an energization capacity equivalent to 40W, so that both are equivalent to 60W, and the bottom two are 60W. The current-carrying capacity is considerable. The difference in energization capacity can be easily obtained by the difference in duty ratio of energization or any way. By utilizing such a difference in energization capacity, fine heating control according to various conditions such as the total number at the time of rice cooking, condensation at the time of heat retention, whitening, and browning due to drying can be performed.

  Various electric rice cooking modes, cooking modes, and heat retention modes can be executed as described above. However, in the present embodiment, in order to use a non-metallic pan such as a clay pan as the pan 1, it is advantageous to increase the heating by a heating source such as the heater 5a provided on the metal barrel frame 11a. The expansion to the dark heating coil 4a, specifically, the heating coil 4a2 side, is caused by the magnetic action of induction heating from the heating coil 4a, that is, the heating element 4b facing the heating coil 4a2, specifically the heating element 4b2. In order to cope with the adverse effect and not leading to stable and good rice cooking, the body portion of the resin interior case 11 is a metal body frame 11a, and the metal body frame 11a is made of nonmagnetic metal. This prevents the magnetic action from occurring between the heating coil 4a, specifically, the alternating magnetic field around the heating coil 4a2. There are various types of such non-magnetic metals including copper and aluminum. In this embodiment, for example, SUS304 is adopted, which is excellent in dirt resistance, corrosion resistance, external force resistance, and the like.

  As described above, the metal body frame 11a is made of nonmagnetic metal, so that the heating coil 4a between the bottom portions of the inner and outer cases 11, 12 is expanded to the immediate vicinity of the magnetic field around the heating coil 4a2 in the outer peripheral portion. Of course, even if the metal barrel frame 11a enters the magnetic field region, the metal barrel frame 11a is a non-magnetic metal, so it hardly generates heat and has little energy loss or influence on the surroundings. A non-magnetic material that does not contain a so-called ferromagnetic material that contains Ni as its main component and does not include a ferromagnetic material, and its remanent magnetization is negligible compared to a ferromagnetic metal, and is induced from the heating coil 4a1 or the like to the heating element 4b2 or the like facing it. The heating action is not hindered or changed, and the heating of the pan 1 can be effectively assisted by the expanded amount.

  As a result, the side heating source 5 is provided on the metal barrel frame 11a of the interior case 11 in the main body 2 that accommodates the pan 1, and the side portion of the pan 1 is heated via the metal barrel frame 11a. Not only when the body frame 11a is made of a non-magnetic metal and is in the immediate vicinity of the magnetic field around the heating coil 4a2, but the energy loss caused by the non-metal body frame 11a is also reduced even if it is expanded to enter the magnetic field. The effect is very small, and the induction heating action between the heating coil 4a2 and the heating element 4b2 is not inhibited or changed with negligible residual magnetization, and the heating of the pan 1 is performed in proportion to the expansion. It can assist effectively, heating characteristics improve without the problem of local overheating by heating coil 4a2, and good rice cooking is realized also with nonmetallic pan 1 with low heat conductivity, such as a clay pot.

  As shown in FIGS. 1 and 2, the side heating source 5 includes a plurality of heaters 5a provided in the vertical direction, specifically, four heaters 5a, etc., and the lowermost heater 5a is located in the vicinity of the heating coil 4a1. In addition to the metal body frame 11a, the lowermost heater 5a also extends to the magnetic field around the heating coil 4a2, and since it is a heater that generates heat due to Joule heat, the eddy current generated by the magnetic field around the heating coil 4a2 However, since it generates heat, the heating function at a predetermined position by the lower heater 5a can be enhanced without being affected by the presence of the metal body frame 11a, and it is effective for cooking in the non-metallic pan 1. .

  On the contrary, the heater 5a below the side heating source 5 is made of a conductive material that does not generate or is hardly induced by an alternating magnetic field around the heating coil 4a2, and is covered with an insulating material having good thermal conductivity. Even if the side heating source 5 enters the magnetic field region around the heating coil 4a2 to effectively use the metal barrel frame 11a and the side heating source 5 for heating the pan 1 by extending the heating source 4a2 side, Since the alternating magnetic field does not cause or is hardly induced, it is possible to prevent mutual influences.

  On the other hand, the metal body frame 11a is not limited to a non-magnetic metal by stopping the boundary position with the resin-made lower frame 11b below the metal body frame 11a close to the alternating magnetic field affected area around the heating coil 4a2. Therefore, even if it is a magnetic metal, the bottom heating source formed by the heating coil 4a2 and the heating element 4b2 facing the heating coil 4a2 is expanded by extending the side heating source 5 in the vicinity of the magnetic field around the heating coil 4a1. It is possible to assist the heating of the pot 1 without causing any interaction with 4.

  More specifically, the metal body frame 11a is located slightly below the upper end of the interior case 11 at the boundary with the resin upper frame 11c, and the boundary with the resin lower frame 11b is the heating of the outer periphery. It is located near the upper end of the coil 4a1. More specifically, the upper end of the metal body frame 11a is positioned approximately 1/6 lower than the upper end of the opening with respect to the overall height of the pan 1, and the lower end is approximately 5/5 lower than the upper end of the opening with respect to the overall height of the pan 1. It is located about 6 down. On the other hand, the stepped portion D of the pan 1 is located at a position approximately halfway or slightly below the overall height of the pan 1, and the lowermost heater 5a is positioned below the stepped portion D of the pan 1 and is thin. It faces the upper end of the half 1b. Thereby, it becomes the structure which is easy to assist the heating from the lower half part 1b of the pan 1 at the time of rice cooking. In addition, the uppermost heater 5a is approximately at the middle height of the facing portion 1e, and the two upper heaters 5a are combined with the two lower heaters 5a within the range of the middle height of the facing portion 1e where the pan 1 is thick. Oppositely, the cooperation with the lid heating source 6 makes it easy to contribute to uniform heat retention of the rice.

  In the present embodiment, the heat from the heating elements 4b1, 4b2 provided on the outer surface of the pan 1 is radiated to the interior case 11 side and the heating coils 4a1, 4a2 by the amount that the heat is not efficiently transmitted to the pan 1 side. If the heating temperature at the time of cooking is increased in order to secure the cooking temperature, the ratio of cooking will be high, and if the heating temperature at the time of cooking is increased, especially the heating element 4b1 that becomes this local overheating part, etc. In order to cope with deterioration and melting damage of the lower frame 11b of the interior case 11 due to heat dissipation of the interior case, and abnormal heat generation of the heating coil 4a1 and the like, the rice cooker and the safety of use are impaired. A magnetically permeable heat-resistant plate 31 is disposed in a portion of the pan 11 of the frame 11b facing the heating element 4b1 where the radial width is large and the total calorific value is large, so that the heat from the heating element 4b1 is reflected. There. However, a heat-resistant plate 31 may be provided in a portion facing the heating element 4b2 to perform the same function.

  Thus, the magnetically permeable heat-resistant plate 31 provided in the main body 2 at the facing portion of the inner case 11 facing the heating element 4b1 provided on the outer surface of the pan 1 is at least the bottom of the inner and outer cases 11 and 12 by the magnetic permeability. It does not impair the effect of inducing heat generation by applying an alternating magnetic field to the heating element 4b1 on the outer surface of the pan 1 facing the heating coil 4a1 provided therebetween. Moreover, this heat-resistant heat-resistant plate 31 is made of a non-metallic material such as a clay pot, which has a low thermal conductivity, whereas the heating element 4b1 on the outer surface of the pot 1 generates heat at a high temperature necessary for good rice cooking. Even if the ratio of heat radiation from the heating element 4b1 or the like to the outer surface of the interior case 11 is high, the heat radiation is reflected on the surface of the heat-resistant plate 31 to the pan 1 side, so Heating efficiency can be improved by heating again and using it again for cooking rice. As a result, good cooking with uniform and sufficient heating corresponding to the object of the present invention is realized from the combination of the non-metallic pot 1 with the thick and easy-to-heat characteristics. Furthermore, the heat-resistant plate 31 is not deteriorated or damaged due to its heat resistance, and heat from the heating element 4b1 on the outer surface of the pan 1 does not reach the interior case 11, particularly the lower frame 11b and the heating coil 4a1 of the main body 2. In addition, it is possible to avoid heat from reaching the outer case 12 of the main body 2.

  According to the combination of the above heating assistance from the side heating source 5 and the heat reflection by the heat-resistant plate 31, even in the case of the non-metallic pan 1, the electric rice cooker and the safety of use are not impaired, and uniform heating is used. Better cooking rice is achieved.

  Here, the heat-resistant plate 31 is preferably made of a non-metal or non-resin material in terms of magnetic permeability and heat resistance, and a ceramic type is suitable for forming the mold, heat resistance, and reflecting surface. If the surface facing the heating element 4b1 is a white reflecting surface, the heat absorption is avoided and the reflectance can be increased. When the white of the reflecting surface is ceramic, it is easily realized by the firing temperature, and a glossy specular reflecting surface can be obtained at the same time. Also, if the firing temperature to obtain a white color becomes a problem in other aspects such as durability, even if firing other than white, a white glossy material is pasted or a white glossy surface is painted. Also good. The surface roughness suitable for such a reflective surface may be about 3 to 5 μm, for example.

  Further, the heat-resistant plate 31 reflects the heat from the heating element 4 b 1 and the like to the side of the pan 1, so that an air gap 32 is provided between the pan 1 and the heating element 4 b 1 and the heat-resistant plate 31. In particular, it is desirable that the air gap 32 is a closed space and is opened at least around so as not to generate heat. In the present embodiment, the air gap 32 is an annular formed on the outer periphery of the bottom of the pan 1. 2 at the height around which the leg 1d is supported by the elastic support 33 made of silicon rubber or the like shown in FIG. 2 provided at about three places on the circumference of the bottom outer periphery of the lower frame 11b. Just secure. However, the air gap 32 can also be secured by receiving and suspending the flange 1 c of the opening of the pan 1 by the opening of the main body 2. The placement and support on the elastic support base 33 by the leg 1d of the pan 1 also exhibits the effect of elastic support of the pan 1 and rotation prevention. On the other hand, as shown in FIGS. 1 and 2, the air gap 32 is formed in the entire area between the interior case 11 and the pan 1 while preventing the heat effect from the pan 1 side to the interior case 11 side. The heat is spread between the interior case 11 and the pan 1, and it becomes easy to promote heating efficiency and uniform heating in cooperation with the heating of the pan 1 and the cooked rice, which are made of non-metal thick and low heat conductivity. In particular, the heat-resistant plate 31 provided in the interior case 11 of the main body 2 is likely to make use of the heat reflected by the pan 1 side.

  Furthermore, the heat-resistant plate 31 has a hole 35 in the central portion for bringing the temperature sensor 34 into contact with the pan 1 and is larger than the outer diameter of the opposing heating element 4b1. Thereby, the temperature of the center part of the bottom part of the pan 1 having a high correlation with rice cooking can be detected by the temperature sensor 34 through the hole 35 in the center part. For this purpose, as shown in FIGS. 1 and 2, the temperature sensor 34 is provided in the center of the coil base 15 and is urged upward by a spring, penetrates the lower frame 11b and the heat-resistant plate 31, and always protrudes thereon. The temperature of the pan 1 can be monitored by being in pressure contact with the bottom of the pan 1 placed on the elastic support base 33.

  The pan 1 has a lower half 1b that is thinner than the facing portion 1e facing the side heating source 5. Thus, the pan 1 is housed so as to be detachable from the main body 2, and the cooking of rice and rice is performed by heating from the bottom heating source 4, the side heating source 5 and the lid heating source 6. The lower half 1b of 1 is thinner than the facing part 1e facing the side heating source 5 and has a smaller heat capacity, so that heat from the heating elements 4b1, 4b2 important for rice cooking is used for primary heating by the direct heat conduction. The secondary heating by the heat reflected from the heat-resistant plate 31 is obtained, and the heating efficiency is further improved, and sufficient cooking rice heating is realized while suppressing to a relatively low energization capacity, and good rice cooking can be performed. In addition, the pot 1 is opposed to the side heating source 5 and the portion 1e is thicker than the lower half 1b and has a higher heat storage capacity. It becomes easy to keep the temperature of the rice uniformly based on the characteristics and the heat assistance based on the heating from the side heating source 5 and the heating from the lid heating source 6.

  Moreover, although the pan 1 makes the lower half part 1b facing the bottom heating source 4 thinner than the facing part 1e facing the side heating source 5, the thickness of the facing part 1e facing the side heating source 5 is larger. The drop-resistant strength is not impaired by the cooperation. In particular, the required strength when falling in an upright posture is satisfied. And the high output heating from the bottom heating source 4 makes the rice cooking heat easier to live by the amount that the lower half 1b that is opposite to the bottom heating source 4 is thin and the heat storage capacity is small, and thick side heating The heat transfer to the facing portion 1e with the source 5 is also promoted. Therefore, the rice in the uniform heating accompanied by the active convection in the water in the pan 1 and the whole area of the rice is realized. Here, it can be said that the side of the pan 1 is thick at the top and thin at the bottom including the bottom rounded portion of the pan 1, but the thin region extends to the side region where the drop resistance strength of the pan 1 is full. By doing, the rice cooking characteristic in the uniform heating by the high output heating from the bottom part heating source 4 using the thin part of the pan 1 further increases. The thick portion and the thin portion of the pan 1 are continuous by forming a rounded step portion D on the outer surface of the pan 1, and a relatively rapid change in thickness is achieved without stress concentration.

  Here, if one example is shown, it is made of a ceramic mainly composed of mullite and cordierite, and a glass-based glaze where the mainstream is a uniform thickness of about 10 to 15 mm in a normal clay pot. For the pan 1 that has been sealed, the thickness of the lower half 1b, which is the facing portion to the bottom heating source 4, is about 3 to 4 mm, and the thickness of the facing portion 1e to the side heating source 5 is about 7 to 8 mm. Sufficient drop-proof strength was obtained, and rice cooked by uniform heating and uniform heat retention were realized. From such a dimensional relationship, the difference in thickness between the thick portion and the thin portion of the pan 1 can be approximately doubled. In addition, since there is no heating source between the facing part of the pan 1 facing the metal body frame 11a which is a heat radiating plate of the heater 5a and the part having the heating element 4b2 facing the heating coil 4a2, there is no heating source. The smaller the thickness, the more advantageous for uniform heating during cooking, and it is preferable that the thickness is about 3 mm. In some cases, the thickness is set in the lower half 1b of the pan 1 on condition that the drop-proof strength is satisfied. It may be thinner.

  Further, according to the experiments of the present inventors, the heat generation amount of the heating elements 4b1, 4b2 tends to show a temperature distribution in which the temperature is high in the central part and the temperature is low on the peripheral side in the radial direction. The temperature difference becomes larger as the thickness of the pan 1 increases. Even if the pan 1 is made of a non-metal having low thermal conductivity, the lower half 1b of the pan 1 is opposed to the side heating source 5 as described above. In the configuration where the thickness is made thinner, the temperature distribution as described above is somewhat reflected as the heating unevenness at the time of rice cooking, so that the temperature unevenness is suppressed to a level that does not cause any problem by making a difference in the thickness of the heating elements 4b1 and 4b2. ing. Specifically, the heating element 4b2 has a smaller width in the radial direction and a smaller temperature distribution than the heating element 4b1, so that the central part in the radial direction is thin and the peripheral part is thick. On the other hand, since the heating element 4b1 has a large width dimension in the radial direction and a large temperature distribution difference, the heating element 4b1 at the central part where the temperature becomes high is eliminated, or the ratio of the thickness of the central part to the thickness of the peripheral part is The heating element 4b2 is made smaller than the case. This improved the uneven heating during cooking. This is because if there is a partial thickness difference between the heating elements 4b1 and 4b2, the amount of current is concentrated and the amount of heat generation is greater than that of the thin-walled portion. It seems to be due to this. Such a partial thickness difference can be easily realized by partially changing the number of times of application, and a portion of thickness 0 where no heating element is provided can be realized by omitting application of the heating element. Here, if two examples of L-2 (100 size) and K (150 size) are shown, suitable results were obtained as a dimensional relationship and a thickness relationship as shown in FIG.

  Corresponding to the high power heating from the bottom heating source 4 as described above, the resin part of the inner case 11 is conventionally formed of PP together with the resin part of the outer case 12, but the heat resistant temperature is as low as about 150 ° C. Since there is a concern about thermal influence, in this embodiment, the upper frame 11c and the lower frame 11b are made of PPS having a high heat resistant temperature of about 250 ° C., and adhesion of the heat resistant plate 31 to the silicon-based adhesive can be achieved without any problem. ing. On the other hand, the bottom member 12a and the shoulder member 12c of the outer case 12 are made of resin such as PET as usual. In addition, as shown in FIG. 2, recesses 41 for facilitating clues to the flange 1c are formed between the shoulder member 12c and the flange 1c of the pan 1, as shown in FIG. A handle 118 that reaches the shoulder member 12c and is supported is provided on the upper portion of the body 12b.

  The present invention is practically used in an electric rice cooker that employs a non-metallic pan, and a metal body frame is provided in the interior case of the main body to ensure the safety against attaching and detaching the pan, or to install a side heating source. While being effective, the mutual influence on the electromagnetic action with the heating coil in the bottom of the main body can be prevented.

It is sectional drawing in the front-back direction which shows one example of the electric rice cooker which concerns on embodiment of this invention. It is sectional drawing in the left-right direction of the electric rice cooker of FIG. It is explanatory drawing which shows the difference in the relationship of the size of the heat generating body in two examples provided in the center part of the bottom part of the pot of the electric rice cooker of FIG. 1, and a peripheral part, and the percent of silver per unit area. .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pan 2 Main body 3 Cover body 4 Bottom part heating source 4a Heating coil 4a1, 4a2 Heating coil 4b Heating body 4b1, 4b2 Heating body 5 Side heating source 5a Heater 5c Holding plate 11 Interior case 11a Metal trunk part frame 11b Lower frame 12 Exterior case

Claims (2)

By disposing heating coil between the bottom of the body of the interior and exterior case, so as to induction heating by the alternating magnetic field of the heating element from the heating coil provided in the portion facing the heating coil of the soil pot accommodated in the main body, made of resin The inner case body is made of a metal body frame and a side heating source is arranged around the outside. By making this metal body frame made of a non-magnetic metal, magnetic action is produced between the alternating magnetic field around the heating coil. and it was not so, as thin a lower half portion from the upper portion of the soil pot halfway height portion on the outer surface from the inner surface side in order to assist heat transfer to the pot inward from the heating element of the outer surface to secure drop strength, heat A gap between the coil and the interior case located between the coil and the lower half corresponds to a larger gap than the upper part to form an air gap that radiates the heat radiated from the heating element, and the earthenware pot absorbs the height error in molding. Of the interior case Supporting the parts, electric rice cooker, characterized in that it suppresses the variation in the distance between the heating element and the outer case. By disposing heating coil between the bottom of the body of the interior and exterior case, so as to induction heating by the alternating magnetic field of the heating element from the heating coil provided in the portion facing the heating coil of the soil pot accommodated in the main body, made of resin The inner case body is made of a metal body frame and a side heating source is arranged around the outside. By making this metal body frame made of a non-magnetic metal, magnetic action is produced between the alternating magnetic field around the heating coil. and it was not so, as thin a lower half portion from the upper portion of the soil pot halfway height portion on the outer surface from the inner surface side in order to assist heat transfer to the pot inward from the heating element of the outer surface to secure drop strength, heat A gap between the coil and the interior case located between the coil and the lower half corresponds to a larger gap than the upper part to form an air gap that radiates the heat radiated from the heating element, and the earthenware pot absorbs the height error in molding. Of the interior case Supported in part, suppress variations in the distance between the heating element and the outer casing, the side heating source a plurality vertically, electric cooker heating source lowermost located in the vicinity of the heating coil.

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