JP2006034595A - Rice cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rice cooker capable of preventing uneven boiling of rice such as partial softness or hardness of the boiled rice, and boiling rice to look delicious. <P>SOLUTION: The rice cooker 50 comprises an inner pot 28, a rice cooker body 1 with an opening on the upper surface and an inner pot storage part 1B for storing the inner pot 28 in the interior from the opening, a lid body 4 for closing the opening of the inner pot storage part 1B openably/closably, a heating means (an induction heating coil 29) disposed facing the inner pot 28 with a prescribed gap at the center for heating the inner pot 28, and an inner pot temperature detecting means (a temperature sensor device 60) for detecting the temperature of the inner pot 28 while boiling rice. In addition, a center heating means (a plate heater 54) is disposed in the center gap of the heating means (the induction heating coil 29), abutting to the center on the outer bottom of the inner pot. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rice cooker, and more particularly to a rice cooker provided with a center heating means capable of heating the center of the bottom of the inner pot.

  A conventional rice cooker, for example, a so-called IH rice cooker using an induction heating coil as a heating means is a rice cooker body 101 pivotally supported by a rice cooker body 101 having an opening 102 on the upper surface and a hinge portion 117 as shown in FIG. A lid 104 that is attached to 101 and closes the opening 102 of the rice cooker body 101 so as to be openable and closable, a handle 103 that is attached to both sides of the rice cooker body 101, and the like. A rear space 142 is formed below the hinge 117. A cord reel 48 around which a power cord is drawn out and stored is disposed in the rear space 142. A plug that can be connected to a commercial AC power source is provided at the end of the power cord.

  Further, a pressable hook button 106 for opening the lid 104 is provided at the front upper portion of the rice cooker body 101, and a steam cartridge 112 for releasing steam generated during rice cooking is provided at the center of the upper surface of the lid 104. Is provided. The body portion 101A of the rice cooker body 101 projects forward by a predetermined dimension, and displays an operation button for performing the rice cooking operation of the rice cooker 100 on the upper portion thereof, a rice cooking menu, a process during the rice cooking operation, and the like. A display unit 110 is provided.

  The display unit 110 displays the current time, timer display, rice cooking menu, and the like. A front space portion 140 is formed in the body portion 101A projecting forward, and an operation board 115 is disposed in the front space portion 140 corresponding to the operation buttons, and the power supply board 126 or A control device (not shown) and the like are provided.

  The rice cooker main body 101 is provided with an inner pot 128, an annular induction heating coil 129, and the like. The inner hook 128 is made of a magnetic material such as iron or stainless steel. The induction heating coil 129 is configured by a coil wound in a spiral shape on the outer side at a predetermined interval from the central portion of the inner pot 128. The induction heating coil 129 is held on the coil base 132 by a ferrite 136 having an effect of reducing noise emitted from the induction heating coil 129 (see Patent Document 1).

JP 2001-17314 A

  The rice cooker 100 configured in this manner generates an alternating magnetic field by causing a current to flow through the induction heating coil 129 during rice cooking in the rice cooking operation. Then, the inner pot 128 is induction-heated by the generated alternating magnetic field. Thereby, the inner pot 128 is heated, and the rice stored in the inner pot 128 is cooked.

  During rice cooking, the temperature at the bottom of the inner pot 128 is detected by a temperature sensor 162 that is brought into contact with the center of the bottom of the inner pot 128 from below. A curve that captures the temperature change at the bottom of the inner pot 128, that is, the change over time of the temperature at the bottom of the inner pot 128 in the rice cooking process of the rice cooker 100 is shown in the graph of FIG. In FIG. 12, the vertical axis indicates the temperature axis (0 ° C. to 140 ° C.) that increases as it goes upward, and the horizontal axis indicates the time axis (0 minutes to 45 minutes) that elapses as it goes right. The curve in the figure is a temperature curve TP1 at the bottom of the inner pot 128 detected by the temperature sensor 162 in the rice cooking process.

  This temperature curve TP1 is TP1A for the preheating process for promoting rice water absorption by the rice cooker 100, TP1B for the heating process for determining the amount of rice cooked by the temperature rise curve and the rice cooking amount determination for boiling. TP1C is the rice cooking process that continuously cooks rice, the water in the inner pot 128 decreases due to continued boiling, the rice temperature rises, TP1D is the dry-up that is the point to detect it, TP1E is the steaming process, and the heat retaining process Is indicated by TP1F.

  In rice cooking of the rice cooker 100 having such steps, boiling starts when a current flows through the induction heating coil 129 and the bottom of the inner pot 128 is heated. Bubbles and steam are continuously generated at the bottom of the inner pot 128 in the rice cooking process TP1C due to the heating. However, since the induction heating coil 129 is wound outwardly at a predetermined distance from the center, Boiling starts near the outer periphery of the bottom of the pot 128.

  There is a high probability that bubbles and steam continuously generated during boiling rise along the inner peripheral side wall of the inner pot 128 and escape into the outside air. Moreover, the bubble and vapor | steam which generate | occur | produce continuously after a boiling start have the tendency for the probability that the path | route which passed first becomes a path | pass until the end of cooking rice. When boiling begins in the rice cooker 100 having the annular induction heating coil 129 in this way, a path through which bubbles pass in an annular shape along the inner peripheral side wall of the inner pot 128 is formed, and bubbles and steam are generated until the end of rice cooking. It was rising along that path.

  In the rice cooker equipped with the annular heating means as described above and the induction heating coil as described above in the prior art, since the heating means is not disposed at the center of the induction heating coil, that is, the center of the bottom of the inner pot, There was a tendency to be difficult to heat, and temperature irregularities sometimes occurred in the temperature of the rice inside the inner pot during cooking. Examining the case where the temperature unevenness occurs in this way, the temperature of the inner pot central portion was low. When it became such a state, there was a possibility that the cooked rice unevenness such as the cooked rice being soft or hard would occur.

  In addition, in order to increase the temperature of the center portion of the inner pot bottom in order to solve such a problem of rice cooking unevenness, if the annular induction heating coil is simply tightly wound to the center portion, the center of the inner pot bottom portion is reversed. Too much heating. Also, as mentioned above, when boiling starts in the rice cooking process, there is a high probability that bubbles and steam will continue to pass through the first path until the end of rice cooking, so the heating at the center of the bottom of the inner pot will continue. Then, only the central part where the temperature rises will boil. For this reason, the overcooking phenomenon which the center part of the inner pot becomes too soft occurred, and there was a problem that uneven cooking of rice occurred. In addition, since the induction heating coil is formed in an annular shape, the portion facing the induction heating coil of the inner kettle boils, and a phenomenon that an unevenness like a crater is formed in the center of the surface occurs, Sometimes it looked bad.

  The present invention has been made in view of the above-mentioned problems, and cooked rice can be cooked with delicious rice that prevents cooked rice unevenness such as partially soft or hard, and also has a beautiful appearance. The purpose is to provide a vessel.

  In order to achieve the above object, a rice cooker according to the present invention has an inner pot, an opening on the upper surface, and a rice cooker body provided with an inner pot accommodating portion in which the inner pot is accommodated from the opening. A lid that closes the opening of the inner pot accommodating portion so as to be openable and closable, a heating unit that is disposed opposite to the inner pot so as to have a predetermined gap in the center, and heats the inner pot, An inner pot temperature detecting means for detecting the temperature of the inner pot, and provided with a center heating means that is in contact with a substantially central portion of the inner bottom surface of the inner pot and disposed in a central space of the heating means. It is characterized by.

  According to the present invention, since the center heating means is disposed in the center portion of the inner pot bottom surface and the heating means is disposed around the center heating means, it is possible to improve the heating state of the center portion of the inner pot bottom surface which tends to be insufficiently heated. .

Embodiment 1 FIG.
Hereinafter, the present invention will be described in detail based on an embodiment of the present invention. FIG. 1 is a longitudinal side view of a rice cooker 50 in one embodiment of the present invention, FIG. 2 is a plan view of a heater device 52 constituting the rice cooker 50 in one embodiment of the present invention, and FIG. 3 is a rice cooker of FIG. FIG. 4 is a plan view of a sensor device constituting the rice cooker 50 in one embodiment of the present invention, and FIG. 5 is a temperature sensor device constituting the rice cooker 50 of FIG. 60 shows vertical side views.

  A rice cooker 50 according to the present embodiment has an inner pot 28 made of a magnetic material such as iron or stainless steel as shown in FIG. 1 and an opening 2 on the upper surface. A rice cooker main body 1 having an inner pot accommodating portion 1B to be accommodated, a lid 4 attached to the rice cooker main body 1 for closing the opening 2 so as to be openable and closable, and steam generated during rice cooking provided on the lid 4 Is formed with a steam cartridge 12 for discharging the rice and the handle 3 attached to both sides of the body 1A of the rice cooker body 1. The inner hook 28 in the present embodiment has a multilayer structure composed of a layer made of a magnetic material that generates heat by induction heating and a non-magnetic material such as aluminum having good thermal conductivity.

  The body portion 1A of the rice cooker body 1 is projected forward by a predetermined dimension, and an operation button (not shown) for performing the rice cooking operation of the rice cooker 50, a display unit 10 and the like are provided on the upper portion of the overhang portion. Yes. The display unit 10 is provided with a liquid crystal display 9 having a liquid crystal substrate. The liquid crystal display 9 displays a current time, a timer display, a rice cooking menu, a process during a rice cooking operation, or the like. An operation board 15 is disposed below the operation buttons corresponding to the operation buttons, and a control device 27 (corresponding to the control means of the present invention) including a general-purpose microcomputer is disposed on the operation board 15. ing. The body portion 1 </ b> A has a front space portion 40 formed inside a protruding portion that protrudes forward, and a power supply substrate 26 is disposed in the front space portion 40.

  Further, the body 1A is provided with a pressable hook button 6 for opening the lid 4 in the vicinity of the lid 4 and pivotally supports the lid 4 so that it can be opened and closed at the rear of the trunk 1A. A hinge portion 17 is provided. A rear space portion 42 is formed below the hinge portion 17, and a shoulder member 18 is provided near the hinge portion 17 in the rear space portion 42. A cord reel 48 around which a power cord is drawn out and stored is disposed in the rear space 42 below the shoulder member 18. A plug that can be connected to a commercial AC power source is provided at the end of the power cord.

  In addition, an induction heating coil 29 (corresponding to the heating means of the present invention) is disposed in the rice cooker body 1 so as to face the bottom of the inner pot 28 accommodated in the inner pot accommodating portion 1B. The induction heating coil 29 is in close contact and wound in a spiral shape a plurality of times or a dozen times, and an annular inner coil 29A having a predetermined gap with an opening at the center, and a predetermined interval from the inner coil 29A. The outer coil 29B is also provided on the outer side and is also in close contact with each other and is wound in a spiral shape a plurality of times or a dozen times. The inner coil 29A and the outer coil 29B are constituted by a single coil, and the inner coil 29A and the outer coil 29B have a portion in which the coil is roughly wound around or about a half turn. . It should be noted that the present invention can be applied to a configuration in which the inner coil 29 </ b> A and the outer coil 29 </ b> B are configured as separate coils without being limited to such a form.

  The induction heating coil 29 is held on the coil base 32 by a ferrite 36 having a magnetic shielding effect, and the ferrite 36 reduces noise emitted from the inner coil 29A and the outer coil 29B. The ferrite 36 that holds the induction heating coil 29 on the coil base 32 has a magnetic shielding effect, and can be a non-metallic material such as carbon, ferrite, or the like as long as it is a material that reduces noise emitted from the induction heating coil 29. It may be made of a synthetic resin containing a non-metallic material having a magnetic shielding effect such as carbon.

  A substantially central portion of the coil base 32 is formed with a through hole (not shown) penetrating vertically, and a temperature sensor provided with a temperature sensor 62 for detecting the temperature of the inner pot 28 at the central portion of the coil base 32. A device 60 (corresponding to the inner pot temperature detecting means of the present invention) is provided. The temperature sensor device 60 protrudes by a predetermined dimension in the direction of the inner hook 28, and a heater device 52 having an annular plate heater 54 (corresponding to the central heating means of the present invention) is disposed around the temperature sensor device 60. Yes.

  In the present embodiment, a temperature sensor device 60 having a circular top surface is provided at the lower center of the inner pot 28, a donut-shaped heater device 52 is provided around the temperature sensor device 60, and an annular induction heating coil 29 is provided therearound. The temperature sensor device 60 and the heater device 52 project from the center of the coil base 32 by a predetermined dimension in the direction of the opening 2 of the rice cooker body 1 and are in contact with the bottom of the inner pot 28. That is, the plate heater 54 is disposed in the central space of the induction heating coil 29, and the plate heater 54 is configured to be movable up and down so as to abut the substantial center of the outer bottom surface of the inner hook 28.

  As shown in FIG. 3, the heater device 52 includes a plate heater 54, an outer case 56 having a substantially U-shaped cross-section opened on the side away from the inner hook 28, and an inner case 58 provided inside the outer case 56. It is configured. The outer case 56 is formed on a flat surface whose upper surface can be substantially in close contact with the bottom of the inner hook 28. As shown in FIG. 2, the plate heater 54 is composed of an electrothermal heater, for example, a donut-shaped ceramic heater whose center is hollowed out in a substantially circular shape, and the outer case 56 is also formed in a donut shape and is formed in the opening. The plate heater 54 can be stored. The inner case 58 is also formed in a donut shape like the outer case 56, and is formed so as to be fitted into the opening of the outer case 56. In the present embodiment, as shown in FIG. 3, the center portion side of the inner case 58 extends downward by a predetermined dimension (in the direction in which the lid 4 is separated), and the end portion is at least 2 facing the center of the inner case 58. The latching | locking part 58A of the location is formed.

  In the heater device 52, the plate heater 54 is accommodated in the opening of the outer case 56, and the inner case 58 is fitted inside thereof, and the outer case 56 and the inner case 58 are spot welded or caulked. Fixed and configured. As a result, the plate heater 54 is held and fixed between the outer case 56 and the inner case 58. A first coil spring accommodating recess 58B that opens downward is formed around the upper part of the inner case 58, and the first coil spring accommodating recess 58B is formed on the lower surface side of the plate heater 54 (on the side away from the lid 4). Has been.

  The plate heater 54 is connected to the control device 27 by wiring (not shown). The control device 27 heats the induction heating coil 29 and the plate heater 54 based on the detection information of the temperature of the inner pot 28 detected by the temperature sensor 62. Each output can be controlled separately.

  As shown in FIGS. 4 and 5, the temperature sensor device 60 (corresponding to the inner pot temperature detecting means of the present invention) includes a temperature sensor 62 and a cylindrical temperature sensor that houses the temperature sensor 62 and has an open upper surface. The holder 64 includes a cap 68 that closes the upper surface opening of the temperature sensor holder 64. The temperature sensor 62 is made of a semiconductor such as a thermistor, and the temperature sensor 62 is attached in close contact with the cap 68 without a gap. Further, a lead wire 62A is connected to the temperature sensor 62, and this lead wire is connected to the control device 27 by wiring.

  The cap 68 of the temperature sensor device 60 is formed with a smaller diameter than the outer case 56 of the heater device 52. As a result, the top surface of the heater device 52 and the top surface of the temperature sensor device 60 come into contact with each other, and the temperature sensor 62 is configured not to directly detect the temperature of the plate heater 54 when detecting the temperature of the bottom of the inner hook 28. is doing.

  Further, the temperature sensor holder 64 is provided with a flange portion 66 extending a predetermined dimension in the circumferential direction of the temperature sensor holder 64. The periphery of the flange portion 66 is bent downward (on the side away from the cap 68) and extends a predetermined dimension, and a second coil spring accommodating recess 66B is formed inside thereof. The flange portion 66 of the temperature sensor holder 64 is provided with a locking hole 66A corresponding to the locking portion 58A provided in the inner case 58 of the heater device 52.

  Then, as shown in FIG. 6, the first coil spring 59 (corresponding to the elastic body of the present invention) is accommodated in the first coil spring accommodating recess 58 </ b> B provided in the inner case 58 of the heater device 52. Then, the flange portion 66 of the temperature sensor 62 is brought into contact with the first coil spring 59. Next, the first coil spring 59 is pushed and elastically deformed by the flange portion 66, and the locking portion 58 </ b> A provided in the inner case 58 of the heater device 52 is inserted into the locking hole 66 </ b> A of the flange portion 66.

  Then, the locking portion 58A inserted into the locking hole 66A is bent, and the locking portion 58A is locked to the locking hole 66A. As a result, the heater device 52 is detachably attached without being detached from the temperature sensor device 60, and the heater device 52 is always urged toward the bottom of the inner hook 28 by the first coil spring 59. At this time, the top surface of the heater device 52 and the top surface of the temperature sensor device 60 are configured to be substantially flush with each other.

  Next, the second coil spring 70 is housed in the second coil spring housing recess 66 </ b> B formed in the heater device 52. Then, one end portion of the second coil spring 70 is fixed to the flange portion 66 and the other end portion is fixed to the holding plate 34 by spot welding or caulking. That is, the temperature sensor device 60 is fixed to the holding plate 34 via the second coil spring 70, so that the temperature sensor device 60 is detachably attached to the holding plate 34, and the temperature sensor device 60 is attached by the second coil spring 70. Is always urged toward the bottom of the inner hook 28.

  In this manner, the heater device 52 is held by the temperature sensor device 60 by the locking portion 58A, and the temperature sensor device 60 is held by the holding plate 34 by the second coil spring 70. In this state, the heater device 52 and the temperature sensor device 60 are individually configured to move up and down within a predetermined dimension range by the first coil spring 59 and the second coil spring 70, respectively.

  Moreover, since the heater apparatus 52 is hold | maintained at the temperature sensor apparatus 60 and the temperature sensor apparatus 60 is hold | maintained at the holding | maintenance board 34, the heater apparatus 52 and the temperature sensor apparatus 60 may come off in the rice cooker main body 1 inward direction. Absent. Thereby, handling of rice cooker 50 becomes easy. In particular, since the temperature sensor 62 for detecting the temperature of the inner pot 28 is disposed at the center of the annularly formed plate heater 54, the present invention is applied without greatly changing the structure of the conventional rice cooker 50. be able to.

  As shown in FIG. 7, the holding plate 34 is disposed on the fixing member 32A provided on the coil base 32, and the holding plate 34 and the fixing member 32A are fixed by spot welding, caulking, screws, fittings, or the like. . In this state, the top surface of the heater device 52 and the top surface of the temperature sensor device 60 are exposed in the inner pot accommodating portion 1B of the rice cooker body 1 and protrude by a predetermined dimension. In this case, the top surface of the heater device 52 and the top surface of the temperature sensor device 60 are in close contact with the bottom surface of the inner hook 28 and come into contact with each other with a predetermined urging force. As a result, the inner pot 28 can be heated by the plate heater 54 without any loss of heat. Further, the temperature sensor device 60 can reliably detect the temperature at the center of the bottom of the inner hook 28. In addition, the rice cooking operation | movement of the rice cooker 50 is demonstrated later.

  As described above, the temperature sensor device 60 and the heater device 52 that are movable up and down by the coil springs 59 and 70 are provided at the center of the induction heating coil 29. As a result, the temperature sensor device 60 and the heater device 52 can be brought into contact with the bottom of the inner hook 28 independently, so that the temperature sensor device 60 can be reliably brought into contact with the inner hook 28. Therefore, the temperature sensor device 60 can accurately detect the temperature of the inner pot 28. Further, since the heater device 52 can be surely brought into contact with the inner hook 28, the plate heater 54 is surely brought into contact with the bottom surface of the inner hook 28 when the inner hook 28 is accommodated in the inner hook accommodating portion 1B. Can do. Therefore, it is possible to reliably heat the central portion of the inner hook 28 that tends to be underheated.

  In addition, since the plate heater 54 is provided separately from the induction heating coil 29, the heating temperatures of the induction heating coil 29 and the heater device 52 can be controlled separately. In particular, since the plate heater 54 is composed of an electrothermal heater, the structure is simple and the control can be easily performed. As a result, the central portion of the inner pot 28 where no heating source is conventionally arranged can be heated by a heating means different from the induction heating coil 29. Moreover, in the conventional rice cooker, the rice cooking temperature of a center part is low, and the temperature inside the inner pot 28 where the temperature nonuniformity may arise as a whole can be improved. Therefore, the temperature distribution in the inner pot 28 during cooking can be made uniform, the appearance of the cooked rice is beautiful, and delicious rice can be cooked.

  In addition, as a tendency at the time of rice cooking in a conventional rice cooker, the probability that the path through which bubbles first pass through the heating of the induction heating coil wound in a ring and the passage of bubbles first becomes the passage of bubbles and steam until the end of rice cooking However, by providing the heater device 52 (plate heater 54) at the center of the annular induction heating coil 29 as in the present invention, boiling can also be started from the center of the inner pot 28. In this case, since the passage of bubbles and steam can be made at the center, the temperature unevenness of the rice temperature during cooking can be reduced. Thereby, the temperature distribution in the inner pot 28 during cooking can be made uniform, and the phenomenon that can be called temperature unevenness or boiling unevenness can be solved. Therefore, the phenomenon of unevenness like a crater does not occur in the center of the surface of the cooked rice as in the prior art, and it is possible to cook delicious rice that is beautiful to the eye. In this embodiment, the induction heating coils 29A and 29B and the plate heater 54 are heated by the control device 27 based on the detection information of the temperature of the inner pot 28 detected by the temperature sensor 62. Since each is controlled separately, it becomes possible to adjust the passage of bubbles and steam.

  Here, when the induction heating coil 29 is simply tightly wound up to the center portion in order to improve the temperature unevenness at the center portion of the inner pot 28, the heating power at the center portion becomes too strong. Also, it becomes difficult to separately control the center and other parts. Therefore, in the present embodiment, a plate heater 54 that can be controlled separately from the induction heating coil 29 is disposed at the center of the induction heating coil 29. As a result, it is possible to perform control such as stopping heating only at the central part or weakening heating while boiling continues. Therefore, neither the overcooking phenomenon that the rice in the center of the inner pot 28 becomes too soft or the phenomenon that it becomes hard does not occur, and uneven rice cooking does not occur. In addition, after cooking rice, there is no phenomenon such as a crater in the center of the surface of the rice, and it is possible to cook delicious and beautifully cooked rice. In the present embodiment, the central heating means is constituted by the plate heater 54 which is an electric heater, but an induction heating type coil may be used instead of such an electric heater.

Embodiment 2. FIG.
The rice cooker 50 in this embodiment has substantially the same configuration as that of the above-described embodiment. Hereinafter, different parts will be described. The same parts as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted. FIG. 8: has shown the vertical side view of the rice cooker 50 of other one Embodiment of this invention. The rice cooker 50 according to the second embodiment is provided with a heater sensor device 74 in which the heater device 52 and the temperature sensor device 60 are integrated without using the first coil spring 59 provided in the heater device 52 according to the first embodiment. .

  Specifically, as shown in FIG. 9, the heater sensor device 74 does not form the outer case 56 of the heater device 52 in the form of a donut but forms the upper surface (inner hook 28 side) as a flat surface, and the temperature of the temperature sensor device 60. The sensor holder 64 is configured in substantially the same manner as described above. The temperature sensor 62 is fixed to the approximate center of the outer case 56, and the plate heater 54 is fixed around the temperature sensor 62 by spot welding or caulking, fitting or adhesion. At this time, the temperature sensor 62 and the plate heater 54 are closely fixed to the outer case 56 without a gap.

  Then, the outer case 56 to which the temperature sensor 62 and the plate heater 54 are fixed is fixed to the temperature sensor holder 64 by spot welding, caulking, fitting, or the like. In this case, the periphery of the outer case 56 is brought into contact with the flange portion 66 of the temperature sensor holder 64, and the temperature sensor holder 64 and the outer case 56 are spotted while the temperature sensor holder 64 is in contact with the outer case 56. Fix by welding or caulking.

  Next, the second coil spring 70 is housed in the second coil spring housing recess 66 </ b> B of the temperature sensor holder 64. Then, as described above, one end of the second coil spring 70 is fixed to the flange 66 and the other end is fixed to the holding plate 34 by spot welding or caulking. The holding plate 34 of the heater sensor device 74 configured as described above is disposed on the fixing member 32A provided on the coil base 32 as in the first embodiment, and the holding plate 34 and the fixing member are formed by spot welding, caulking, screws, or the like. 32A is fixed.

  By configuring the heater sensor device 74 as described above, the same effects as those described in the first embodiment can be obtained. Further, since the heater sensor device 74 is configured by integrating the heater device 52 and the temperature sensor device 60 described in the first embodiment, the number of parts and the number of assembly steps can be reduced. Thereby, the cost of the heater sensor device 74 can be reduced, and the cost of the rice cooker 50 can be reduced as a whole.

Embodiment 3 FIG.
Rice cooker 50 in the present embodiment has substantially the same configuration as that of the first embodiment. Hereinafter, different parts will be described. The same parts as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted. FIG. 10 shows a longitudinal side view of a rice cooker 50 according to another embodiment of the present invention. In the rice cooker 50 according to the third embodiment, the temperature sensor 62 (temperature sensor device 60) is disposed at a position separated from the central portion of the inner pot 28 by a predetermined dimension, and the plate heater 54 is provided at the central portion of the inner pot 28. .

  Specifically, the temperature sensor device 60 including the temperature sensor 62 of the first embodiment is disposed between the inner coil 29A and the outer coil 29B, and the cap 68 (temperature sensor 62) of the temperature sensor device 60 is disposed in the inner pot. It can be moved up and down in 28 directions. As a result, the temperature sensor 62 is brought into close contact with the inner hook 28 as described above, so that the temperature of the inner hook 28 can be reliably detected.

  That is, in the third embodiment, the temperature sensor 62 is not provided in the outer case 56 of the heater device 52 described in the first embodiment, and the plate heater 54 is provided in the entire outer case 56. Further, a heater fixture 73 having only a flange portion 66 is provided for the temperature sensor device 60 described above.

  Then, the lower end of the outer case 56 is fixed to the upper surface of the flange portion 66 of the heater fixture 73 by spot welding, caulking, screws, or the like. As described above, one end of the second coil spring 70 is fixed to the flange 66 and the other end is fixed to the holding plate 34 by spot welding or caulking. The holding plate 34 is disposed on a fixing member 32A provided on the coil base 32 as in the first embodiment, and the holding plate 34 and the fixing member 32A are fixed by spot welding, caulking, screws, or the like.

  Thereby, the effect similar to the effect described in Embodiment 1 can be produced. Further, since the temperature sensor 62 is disposed at a position separated from the plate heater 54 by a predetermined dimension, the temperature sensor 62 can be hardly affected by the heat released from the plate heater 54 that generates heat. Thereby, the temperature sensor 62 can easily detect the temperature of the inner pot 28 during rice cooking accurately, and can easily control the temperature of the plate heater 54 during rice cooking. Accordingly, it is possible to prevent the phenomenon that the surface of the surface of the rice is uneven after the cooking, such as a crater, and to cook beautifully delicious rice.

Embodiment 4 FIG.
The operation of the rice cooker 50 described in the first to third embodiments will be described with reference to FIG. Note that the control device 27 individually controls the heating outputs of the induction heating coil 29 and the plate heater 54 based on the temperature detected by the temperature sensor 62. First, in the first example, the control device 27 energizes the plate heater 54 from the start of rice cooking (preheating process TP1A start) for energizing the induction heating coil 29. And the control apparatus 27 performs the control which cuts off the electricity supply to the plate heater 54, or weakens an output at the timing from the predetermined time before the rice cooking amount determination TP1B start at the time of rice cooking amount determination TP1B start. By performing energization control to the plate heater 54 with the control device 27, the central portion of the inner hook 28 can also be heated during the preheating step TP1A.

  In this case, the rice cooking temperature nonuniformity during preheating due to the low temperature of the central portion of the conventional inner pot can be improved. Furthermore, it is possible to prevent inconveniences such as the inner pot temperature sensor 62 detecting the heating temperature of the inner induction coil when the amount of cooked rice is determined. Thereby, an accurate rice cooking amount determination can be performed. In the third embodiment, the heater device 52 and the temperature sensor 62 are separated from each other by a predetermined distance. Thereby, the heat effect which the heater apparatus 52 has with respect to the temperature sensor 62 during rice cooking amount determination TP1B can be made smaller, and the temperature detection by the temperature sensor 62 can be performed easily.

  Next, in the second example, the control device 27 continues energization without weakening or turning off the energization of the plate heater 54 during the rice cooking amount determination TP1B after the preheating step TP1A, or does not energize the preheating step TP1A. In addition, control for starting energization of the plate heater 54 from the preheating step TP1A is performed. In this case, since the center part of the inner pot 28 can be heated even during the rice temperature rise time in the rice cooking amount determination TP1B by high heat heating after the preheating step TP1A is finished, it is easy to start boiling from the center part. Become.

  That is, as shown in the conventional example, in the inner pot, bubbles are continuously generated from the portion where boiling starts, and the portion where the bubbles are continuously generated tends to be a passage of bubbles and steam in the rice cooking. . However, in the present invention, a controllable plate heater 54 is provided separately from the induction heating coil 29, and this plate heater 54 is disposed at the center of the induction heating coil 29, and the control device 27 controls the heating. Thereby, since boiling can be started also from the center part of the inner pot 28, and a bubble can be continuously generated, the phenomenon which can be called boiling nonuniformity can be eliminated suitably. Moreover, since boiling can be started also from the center part of the inner pot 28, the temperature nonuniformity of the inner pot 28 center part can be improved more favorably, and generation | occurrence | production of cooking unevenness can also be prevented. Therefore, it will be possible to cook beautifully delicious rice.

  In this way, by controlling the plate heater 54, the temperature unevenness can be reduced at any point in the rice cooking process, so that the uneven cooking of cooked rice can be eliminated. Therefore, delicious and plump rice can be cooked beautifully and visually. Moreover, since air bubbles are generated evenly in the inner pot 28 during cooking, there are few irregularities like the crater on the cooked rice surface, and it is possible to cook beautifully cooked rice.

  Next, in the third example, the control device 27 performs control to start energization of the plate heater 54 or to increase the output of the plate heater 54 at a timing after the end of the rice cooking amount determination TP1B. In this case, the controller 27 detects the temperature of the plate heater 54 at a timing at which the thermal effect on the temperature sensor 62 can be reduced during the rice cooking amount determination TP1B, which is the time for measuring the temperature of the inner pot 28 by the temperature sensor device 60. Control energization. Thereby, since the temperature measurement error of the inner pot 28 in the temperature sensor 62 can be reduced, more accurate rice cooking amount determination TP1B can be performed.

  In addition, the energization timing of the plate heater 54 is delayed compared to the second example, but bubbles can be generated from the center as in the second example. Thereby, the effect similar to the 2nd example can be acquired.

  Next, in the fourth example, the control device 27 performs control to turn off the plate heater 54 or weaken the output when dry-up TP1D is detected, or from the predetermined time before detecting dry-up TP1D to when dry-up is detected. I do. In this case, when the temperature of the dry-up TP1D is detected, the control device 27 controls the energization of the plate heater 54 at a timing at which the temperature sensor 62 can reduce the thermal effect received from the plate heater 54. Thereby, since the temperature measurement error of the inner pot 28 in the temperature sensor 62 can be reduced, it becomes possible to accurately detect the dry-up TP1D.

  In addition, since the controller 27 continues to boil and drys up the water in the inner pot or when the predetermined time elapses, the plate heater 54 is cut off or the output is weakened. There is no overcooking phenomenon such as the cooked rice becomes soft, and there is no uneven cooking. In addition, it is possible to cook delicious rice that is delicious and visually pleasing without the occurrence of irregularities such as craters in the center of the surface.

  Next, in the fifth example, the control device 27 performs energization control (temperature adjustment) of the plate heater 54 according to the temperature detected by the temperature sensor 62 in each operation of the first to fourth examples, Perform both temperature adjustments. In this case, it is not necessary to provide a special temperature sensor other than the temperature sensor 62 for the purpose of energization control of the plate heater 54. Thereby, rice cooker 50 is realizable at low cost.

Embodiment 5. FIG.
As described in the above first to fourth embodiments, according to each of the above-described embodiments, the plate heater 54 that contacts the central portion of the outer bottom surface of the inner hook 28 is provided in the central space of the induction heating coil 29. Therefore, the heating state of the central portion of the inner hook 28 that tends to be insufficiently heated can be suitably improved.

  Further, since the plate heater 54 that can move up and down within a predetermined range by the first coil spring 59 is provided on the bottom surface of the inner hook accommodating portion 1B, when the inner hook 28 is accommodated in the inner hook accommodating portion 1B, the bottom surface of the inner hook 28 is provided. The plate heater 54 can be reliably brought into contact with. Thereby, the heating state of the central portion of the inner hook 28 that tends to be insufficiently heated can be improved more reliably.

  Further, since the control device 27 individually controls the heating outputs of the induction heating coil 29 and the plate heater 54 based on the temperature detected by the temperature sensor 62, the temperature unevenness in the central portion of the inner pot 28 is reduced. It can be improved better. Thereby, generation | occurrence | production of cooking unevenness can also be prevented. Therefore, it will be possible to cook beautifully delicious rice.

  In particular, since the control device 27 controls the induction heating coil 29 and the plate heater 54 separately, the heating of only the central portion of the plate heater 54 is interrupted, or the heating of only the central portion is weakened, Conversely, it is possible to increase the heating of only the central portion or the heating of only the central portion by cutting off the energization to the induction heating coil 29. As a result, heating suitable for the rice state becomes possible, for example, the overcooking (softening) phenomenon does not occur in the central portion of the inner pot 28, and uneven cooking occurs, or the core remains in the rice due to insufficient heating. Inconvenience can also be prevented. In addition, there is no occurrence of unevenness like a crater at the center of the surface of the inner pot 28 of the cooked rice, and it is possible to cook delicious and beautifully cooked rice.

  Further, the control device 27 energizes / disconnects the plate heater 54 at a timing when the temperature sensor 62 detects the temperature of the inner pot 28 so that the thermal effect from the plate heater 54 received by the temperature sensor 62 is minimized. Since electric power, output strength, and the like are controlled, the temperature at the center of the inner pot 28 during rice cooking can be detected very accurately. Thereby, the rice cooking temperature of the rice cooker 50 can be suitably controlled.

  In addition, since the control device 27 performs the control to cut off the power of the plate heater 54 or weaken the output during the rice cooking amount determination or from the predetermined time before the rice cooking amount determination, the temperature at the time of rice cooking amount determination Inconveniences such as the sensor 62 detecting the heating temperature of the plate heater 54 can be prevented in advance. Thereby, a more accurate rice cooking amount determination can be performed.

  In addition, since the control device 27 performs energization to the plate heater 54 after the rice cooking amount determination, or the control to increase the output, the temperature sensor 62 detects the heating temperature of the plate heater 54. It is possible to prevent inconveniences such as Thereby, the inner pot 28 during cooking can be heated at a suitable temperature.

  Further, the control device 27 performs control to turn off the electric power to the plate heater 54 or to reduce the output when the temperature sensor 62 detects the dry-up, or from the predetermined time before the dry-up is detected. Therefore, the heat influence from the plate heater 54 to the temperature sensor 62 can be reduced at the time of detecting a dry-up in which the temperature rises before shifting from the rice cooking process to the steaming process. Thereby, since the dry-up temperature can be accurately detected, the steaming process can be performed at a suitable temperature. Therefore, it becomes possible to cook even more delicious rice.

  In the first to fourth embodiments, the center heating means has been described with the ceramic plate heater 54. However, the center heating means is not limited to the ceramic plate heater 54, and a graphite plate heater made of a sintered graphite material, The present invention may be applied to other plate-type heaters, or induction heaters similar to the induction heating coil 29 constituted by conductive wires as well as plate-like heaters, or sheathed heaters composed of tubular heaters. The invention is effective.

  In addition, the induction heating coil 29 is configured by a single coil including the inner coil 29A and the outer coil 29B. However, the inner coil 29A and the outer coil 29B of the induction heating coil 29 are configured separately, and they are separately heated. It can be controlled. Thereby, temperature control of the inner hook 28 can be performed more finely. Therefore, it is possible to suitably prevent the temperature fluctuation and cooking unevenness of the inner pot 28 from occurring, and it becomes possible to cook rice that is more delicious and beautiful in appearance.

It is a vertical side view of the rice cooker in one Embodiment of this invention. It is a top view of the heater apparatus which comprises the rice cooker in one Embodiment of this invention. It is a vertical side view of the heater apparatus which comprises the rice cooker of the same FIG. It is a top view of the sensor apparatus which comprises the rice cooker in one Embodiment of this invention. It is a vertical side view of the temperature sensor apparatus which comprises the rice cooker of the same FIG. It is an assembly vertical side view of the temperature sensor apparatus and heater apparatus which concern on one embodiment of this invention. It is a principal part enlarged view of a rice cooker. It is a longitudinal cross-sectional view of the rice cooker which concerns on one embodiment of this invention. It is a principal part enlarged view of the rice cooker of the same FIG. It is a longitudinal cross-sectional view of the rice cooker which concerns on one embodiment of this invention. It is a longitudinal cross-sectional view of the conventional rice cooker. It is a graph which shows the time-dependent change of the temperature of the inner pot bottom which shows the rice cooking process of a rice cooker.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rice cooker main body, 1A body part, 2 opening, 3 handle, 4 lid body, 10 display part, 12 steam cartridge, 27 control apparatus, 28 inner pot, 29 induction heating coil, 29A inner coil, 29B outer coil, 32 coil Base, 32A fixing member, 34 holding plate, 50 rice cooker, 52 heater device, 54 plate heater, 56 outer case, 58 inner case, 58B first coil spring accommodating recess, 59 first coil spring, 60 sensor device, 62 temperature sensor, 64 Temperature sensor holder, 66B Second coil spring accommodating recess, 68 Cap, 70 Second coil spring.

Claims (8)

A rice cooker body having an inner pot, an opening on the upper surface, and an inner pot accommodating portion in which the inner pot is accommodated from the opening, and the opening of the inner pot accommodating portion being closed so as to be openable and closable. A lid, a heating means arranged to face the inner pot so as to have a predetermined gap at the center, and heating the inner pot; and an inner pot temperature detecting means for detecting the temperature of the inner pot during cooking Prepared,
A rice cooker characterized in that a center heating means is provided in contact with the substantially central portion of the outer bottom surface of the inner pot and disposed in a central space of the heating means.   2. The rice cooker according to claim 1, wherein the central heating unit is formed on the bottom surface of the inner pot accommodating portion so as to be movable up and down within a predetermined size range by an elastic body.   3. The rice cooker according to claim 1, wherein the center heating means is formed in an annular shape, and the inner pot temperature detecting means is disposed in a central portion of the annular central heating means.   Control means for controlling the heating output of the heating means and the central heating means based on the detection information of the inner pot temperature detection means, the control means based on the temperature detected by the inner pot temperature detection means The rice cooker according to any one of claims 1 to 3, wherein the heating outputs of the heating means and the central heating means are individually controlled.   The control means controls the center heating so as to minimize the heat effect from the center heating means received by the inner pot temperature detecting means at a timing when the inner pot temperature detecting means detects the temperature of the inner pot. The rice cooker according to claim 4, wherein control of energization, power interruption, output strength and the like of the means is performed.   6. The rice cooking according to claim 5, wherein the control means performs control to cut off the power of the central heating means or weaken the output during the rice cooking amount determination, or from the predetermined time to the rice cooking amount determination. vessel.   The rice cooker according to claim 5 or 6, wherein the control means performs energization to the center heating means to start energization after the rice cooking amount determination or to increase the output.   The control means performs control to turn off the power or reduce the output when the central heating means is energized at the time of dry-up detection by the inner pot temperature detection means, or from the predetermined time before the dry-up detection. The rice cooker according to any one of claims 5 to 7.

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