JP2013233332A - Rice cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rice cooker having an antimagnetic plate to reduce a magnetic field leaking from a cooker body to the outside, and keeping the distance between the antimagnetic plate and a heating coil constant to stabilize heating power and suppress vibration and abnormal noise generated by backlash.SOLUTION: A rice cooker includes a cooker body 101, a pot 102 which can be put in the cooker body 101 freely removably, and a protective frame 103 which accommodates the lower part of the pot 102, wherein the protective frame 103 has a heating coil 104 for inductively heating the pot 102, an antimagnetic plate 108 for reducing the leakage of a magnetic flux generated from the heating coil 104 to the outside of the cooker body and formed of a non-magnetic metal is disposed on an outer side of the protective frame 103, and the antimagnetic plate 108 shows a polygonal shape having at least two or more bent portions.

Description

  The present invention relates to a rice cooker that improves rice cooking performance by high-power heating by electromagnetic induction.

  Conventionally, this type of electromagnetic induction rice cooker has mainly used a pot heating means arranged at the bottom of the pot to heat rice and water in the pot, and by energizing a heating coil arranged below the pot. In general, the pot itself is heated by the generated eddy current to heat the food in the pot. However, in order to prevent magnetic flux from leaking outside the main body of the rice cooker during energization, it has been generally performed to install a magnetic shielding plate outside the side of the heating coil. (For example, refer to Patent Document 1).

  As shown in FIG. 3, the rice cooker having a conventional configuration described in Patent Document 1 is configured with a heat-resistant resin in which a removable pan 1 is housed in the main body and the lower portion of the pan 1 is accommodated. A protective frame 2 is provided, and a heating coil 3 for heating the pan 1 is disposed on the lower surface of the protective frame 2. A magnetic shielding plate 4 having a substantially annular shape made of an aluminum plate made of a strip-like nonmagnetic metal is disposed on the outer side of the heating coil 3. The magnetic shielding plate 4 is provided between a plurality of ribs on the outer periphery of the protective frame 2. It is adapted to be fitted and fixed to.

  In the above configuration, the pot 1 is heated by the heating coil 3 to cook the cooked rice and water. When the heating coil 3 is energized, an eddy current is generated. At the same time that the pan 1 housed in the protective frame 2 is heated, an eddy current is generated in the magnetic shield 4 to cancel the magnetic field passing through the magnetic shield, thereby reducing the magnetic field leaking out of the rice cooker body. It was.

JP 2006-230435 A

  However, in the conventional rice cooker described in Patent Document 1, when the thickness of the aluminum plate, which is a material of the magnetic shield plate, is reduced for the purpose of reducing the weight of the main body in order to improve the usability of the user, The constructed magnetic shield has a problem that its own rigidity is weak and deformation occurs due to a load when it is disposed on the outer periphery of the protective frame.

  In this case, the interval between the heating coil and the magnetic shielding plate changes, leading to the result that the proper cooking power cannot be obtained and the rice cooking performance deteriorates. In addition, the magnetic shielding plate may rattle, causing vibration and abnormal noise.

  The rice cooker of the present invention solves the above-mentioned conventional problems, and is obtained by obtaining a magnetic shield plate having sufficient rigidity even when the magnetic shield plate is made of a thin plate metal, thereby heating the heating coil at a constant interval. It aims at providing the rice cooker which can suppress the vibration and abnormal noise which generate | occur | produce by power stabilization and shakiness.

  In order to solve the conventional problems, the rice cooker of the present invention includes a pan that can be detachably inserted into a main body, and a protective frame that accommodates a lower portion of the pan, and the protective frame induction-heats the pan. And a magnetic shielding plate formed of a nonmagnetic metal that reduces leakage of magnetic flux generated from the heating coil to the outside of the main body, and the magnetic shielding plate has at least two bent portions. It becomes the polygonal shape provided with.

  As a result, the rigidity strength of the magnetic shield plate is improved, and the gap between the heating coil and the magnetic shield plate does not become constant due to deformation at the time of assembly or the like, and a stable heating power can be given to the pan. Moreover, since the strength of the magnetic shield plate is high, it is possible to eliminate the fear of slight vibrations and abnormal noises during induction heating.

  The rice cooker of the present invention can provide a rice cooker capable of suppressing vibrations and noise generated by rattling with a constant heating power while keeping the gap between the magnetic shield plate and the heating coil constant. It is a thing.

Sectional drawing of the rice cooker in Embodiment 1 of this invention. The perspective view of the rice cooker in Embodiment 1 of this invention. Sectional drawing which shows the conventional rice cooker

  The present invention includes a pan that can be detachably inserted into a rice cooker body, and a protective frame that accommodates a lower portion of the pan. The protective frame is generated from a heating coil that induction-heats the pan, and the heating coil. A magnetic shielding plate formed of a nonmagnetic metal that reduces leakage of magnetic flux to the outside of the main body, and the magnetic shielding plate has a polygonal shape with at least two bent portions. It is.

  Thereby, the rigidity strength of the magnetic shield plate is improved, and the distance between the heating coil and the magnetic shield plate does not become constant due to deformation at the time of assembly, and stable heating power can be given to the pan. Moreover, since the strength of the magnetic shield plate is high, it is possible to prevent fine vibrations and abnormal noises during induction heating.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
1 and 2 show a rice cooker according to an embodiment of the present invention. In order to simplify the drawing, lead wires and the like for electrical connection are omitted.

  In FIG. 1, the main body 101 of the rice cooker is provided with a bottomed cylindrical protective frame 103 in which a detachable pan 102 is accommodated, and the pan 102 is detachably accommodated. A heating coil 104 for heating the pot 102 is provided at the bottom of the protective frame 103, and the pot 102 is induction-heated to perform rice cooking and heat insulation. Note that the pot 102 may be heated with a cast heater instead of the induction heating method using the heating coil 104, but it is clear that the pot 102 can be heated with higher heating power and higher efficiency by the induction heating method. It is. The heating coil 104 includes an inner heating coil 104a and an outer heating coil 104b that are divided into an inner side and an outer side. A control circuit 105 that controls the heating coil 104 is disposed behind the main body 101. In addition, a bottom sensor 106 is provided at the center of the bottom of the protective frame 103 so as to contact the bottom surface of the pot 102 and detect the temperature thereof, detect the temperature of the pot 102, send a signal to the control circuit 105, and heat the coil 104. The temperature of the pot 102 is controlled to a temperature suitable for rice cooking and heat retention by controlling the amount of electricity applied to the pot 102 and controlling the amount of heating of the pot 102.

  The protective frame 103 arranges at least four or more ferrites 107 at substantially equal positions outside the heating coil 104 to prevent leakage of the magnetic flux of the heating coil 104 toward the bottom surface and to the pot 102. It works to promote induction heating with high efficiency. Further, a magnetic shielding plate 108 having a polygonal shape with four bent portions 108a made of an aluminum plate, which is a non-magnetic metal having a thickness of about 0.5 mm to 0.6 mm, is provided at the outer peripheral position of the outer heating coil 104b. Is arranged.

  Above the main body 101, an openable / closable lid 110 is installed that covers the opening of the pan 102 and is pivotally supported by a hinge 109. The lid 110 is provided with a packing 111 for sealing the opening of the pan. The lid 110 is detachable from the lid 110 and is mainly provided with a heating plate 112 made of a magnetic metal such as stainless steel. Is provided with a lid sensor 113 that presses against the heating plate 112 and detects the temperature of the upper portion of the pan 102. A lid coil 114 is installed above the heating plate 112, and a lid sensor 113 detects the temperature of the heating plate 112 and communicates with the control circuit 105 to control energization of the lid coil 114, and from the heating plate 112 side. Heating is performed, and proper temperature control of the pot 102 during cooking and heat insulation is performed. Also, a lid engaging portion 115 is provided at the tip of the lid body 110 so that the lid body 110 is not accidentally opened during rice cooking or heat insulation by engaging with the hook button 116 in front of the main body 101 when the lid is closed. I have to.

  The operation of the rice cooker configured as described above will be described. The cooked rice / water prepared in the pan 102 enters the rice cooking process under the control of the control circuit 105. The rice cooking process is roughly divided into “immersion”, “cooking”, and “steaming” processes, and the bottom sensor 106 and the lid sensor 113 detect the temperature of each part while detecting the internal heating coil 104a and the external heating coil 104b. Cooking from the lid coil 114 is performed by heating.

  In order to heat the pan 102 in each process, a magnetic field is generated from the heating coil 104. The generated magnetic field is used as energy for heating the pan 102 on the upper side, but the main body is used for the magnetic field in the lower side or side direction. Leakage downward is prevented by the ferrite 107, and leakage in the side direction is prevented by the magnetic shield 108 so as not to be discharged outside the 101. If the distance between the magnetic shield plate 108 and the outer heating coil 104b is too close, the magnetic field for heating the pan 102 is absorbed, and if it is too far, there is no effect in preventing leakage of magnetic flux, so there is an optimal positional relationship. The inventors have set this distance to about 30 mm. As in the configuration described above, the magnetic shield plate 108 has a certain strength on each side between the four bent portions 108 a and can maintain the necessary distance between the magnetic shield plate 108 and the heating coil 104. The heating power can be stably obtained, and unnecessary vibration during induction heating is reduced.

  As described above, the rice cooker of the present invention is a rice cooker capable of suppressing vibrations and abnormal noises generated by rattling with a constant distance between the magnetic shield plate 108 and the heating coil 104 while stabilizing the heating power. It is designed to provide a vessel.

  As described above, since the rice cooker according to the present invention can stabilize the heating power and prevent unnecessary vibration and noise, it can be applied to other induction heating cooking appliances and the like.

101 Main body 102 Pan 103 Protection frame 104 Heating coil 108 Magnetic shield

Claims (1)

A rice cooker body, a pan that can be removably inserted into the main body, and a protective frame that accommodates a lower portion of the pan, the protective frame is generated from a heating coil that induction-heats the pan, and the heating coil A magnetic shielding plate formed of a non-magnetic metal that reduces leakage of the magnetic flux to the outside of the main body, and the magnetic shielding plate has a polygonal shape with at least two bent portions. Rice cooker characterized by.

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