JP3531478B2 - Electric rice cooker - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rice cooker used in ordinary households. [0002] In recent years, an electric rice cooker utilizing electromagnetic induction heating has been proposed. In FIG. 5, reference numeral 1 denotes a cylindrical body having an open upper surface. Inside the body 1, a coil base 2 serving as a storage portion for a pot 3 is provided. It is formed in a shape. An induction coil 4 is disposed outside the coil base 2. The induction coil 4 is provided with an inner coil 4a opposed to the bottom of the pot and an outer coil provided opposite the side of the bottom of the pot. 4b are connected in series. Further, the induction coil 4 is supported by a ferrite table 5 formed of a heat-resistant resin material on the lower part of the outer periphery of the coil base 2 so that the distance to the outer peripheral surface of the pot 3 is constant. A ferrite 6 is adhered to the ferrite base 5. [0004] However, the conventional rice cooker controls only the ON / OFF of the heating coil, and cannot change the magnetic flux generated from the heating coil. The heating distribution generated by the heat treatment could not be varied. Also, since the direction of convection in the cooking that occurs when the pan is heated is always constant,
Uneven cooking was easy to occur. [0005] In view of the above circumstances, an object of the present invention is to provide a rice cooker in which the convection of cooked food is varied and cooking unevenness is greatly improved. SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention comprises a body, a pot removably housed in the body, and a non-metal part surrounding a bottom side surface of the pot. A heating coil attached to the outside of the coil base and heating the pot by electromagnetic induction, an induction coil located near the heating coil and located on a surface facing the pot, And a switch device for short-circuiting and opening both ends of the coil. According to the first aspect of the present invention, there is provided a body, a pot removably housed in the body, a coil base comprising a non-metal part surrounding a bottom side surface of the pot, A heating coil attached to the outside of the coil base and heating the pan by electromagnetic induction, an induction coil located near the heating coil and located on a surface facing the pan, and both ends of the induction coil are short-circuited. And a switch device for opening. According to this configuration, when both ends of the induction coil are short-circuited by the switch device, the magnetic flux generated in the heating coil passes through the surface of the pot, and an eddy current generated at this time is generated to heat the pot. In addition, the magnetic flux passes through the induction coil section, so that an electromotive current is generated and a magnetic flux that cancels the magnetic flux is generated. Therefore, on the pot surface facing the induction coil, the magnetic flux generated by the heating coil and the magnetic flux generated by the induction coil cancel each other, so that the calorific value of the pan is reduced. Further, if both ends of the induction coil are opened by the switch device, no electromotive current flows through the induction coil even if the magnetic flux generated by the heating coil passes through the induction coil. And generate heat. That is, by short-circuiting and opening both ends of the induction coil, the heat generation distribution of the pan can be varied. By regulating the position of the induction coil, convection in the pan can be varied. Therefore, it is possible to provide a rice cooker with less uneven cooking by varying the convection in the food. (Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. In the drawing, reference numeral 10 denotes a substantially cylindrical body having an open upper surface, reference numeral 11 denotes a coil base formed in a cylindrical shape with a bottom from a non-metallic material, and reference numeral 12 denotes a pan, which is disposed detachably from the body 10. . A heating coil 13 is provided at the bottom of the coil base 11, and an induction coil 14 is provided at the bottom center of the coil base. The heating coil 13 is configured by connecting in series an inner coil 13A disposed on the bottom of the pan and an outer coil 13B disposed on the side of the bottom of the pan. In the heating coil 13, the input ratio of the alternating magnetic field of the inner coil 13A is set high. Further, the heating coil 13 and the induction coil 14 are supported by a ferrite table 15 formed of a heat-resistant resin material on the lower part of the outer periphery of the coil base 11 so that the distance to the outer peripheral surface of the pan 12 is constant. 16 is fixed to prevent the magnetic flux generated from the heating coil 13 from leaking downward, and strengthen the magnetic coupling between the heating coil and the induction coil 14. Also one
Reference numeral 7 denotes a circuit board for supplying a current for generating an alternating magnetic field to the heating coil 13, and reference numeral 18 denotes a switch device provided on the circuit board 13 for short-circuiting or opening both ends of the induction coil 14. 19 is a synthetic resin outer lid. The operation of the above configuration will be described below. When cooked food (not shown) such as rice water is put into the pot 12 and the rice cooker is operated, an electric current flows from the circuit board 17 to the heating coil 13 so that the heating coil 13 generates an alternating magnetic field and heats the pot 12. I do. Here, when both ends of the induction coil 14 are opened by the switch device 18, the convection of the object to be cooked in the pan 12 becomes convection in the direction indicated by a because the input ratio of the alternating magnetic field of the inner coil 13A is high. . Next, the switch device 18
Is short-circuited, an induction current flows through the induction coil 14 due to the magnetic flux generated by the heating coil, and a magnetic flux that cancels the magnetic flux generated by the heating coil 13 is generated in the induction coil 14. Since the magnetic flux generated by the induction coil 14 has a greater effect on the inner coil 13A near the induction coil, the magnetic flux received by the pan 12 by the inner coil 13A is relatively reduced, and the convection to the food is b. Convection in the direction indicated by. The above-described switching is repeated at a predetermined cycle, and the water in the food is absorbed by the rice or evaporated until the water stops evaporating. (Embodiment 2) FIG. 3 shows a rice cooker according to a second embodiment.
It will be described based on. Since a part of the configuration is the same as that of the first embodiment, the description is partially omitted. 21 is a pan, 22 is a heating coil, and is configured by connecting in series an inner coil 22A disposed on the bottom surface of the pan and an outer coil 22B disposed on the side surface of the bottom of the pan. On the outer periphery of the outer coil 22,
An induction coil 23 is provided. The heating coil 22 is also set to have a higher input ratio of the alternating magnetic field of the outer coil 22B. Furthermore, the magnetic coupling between the heating coil and the induction coil 23 is enhanced by the ferrite 24. Reference numeral 25 denotes a circuit board for supplying a current for generating an alternating magnetic field to the heating coil 22, and reference numeral 26 denotes a switch device for short-circuiting or opening both ends of the induction coil 23. The operation of the above configuration will be described below. Pot 2
When a cooker (not shown) such as rice water is put into the cooker 1 and the rice cooker is operated, an electric current flows from the circuit board 25 to the first heating coil 22 so that the heating coil 22 generates an alternating magnetic field and
Heat. Here, when both ends of the induction coil 23 are opened by the switching device 26, the outer coil 22
Since the input ratio of the alternating magnetic field of A is high, the convection of the object to be cooked in the pan 21 is convection in the direction indicated by a. Next, when the switch device 26 is short-circuited, an induction current flows through the induction coil 23 due to the magnetic flux generated by the heating coil, and a magnetic flux that cancels the magnetic flux generated by the heating coil 22 is generated in the induction coil 23. Since the magnetic flux generated by the induction coil 23 has a greater effect on the outer coil 22B near the induction coil, the magnetic flux received by the pan 21 by the inner coil 22B is relatively reduced, and the convection to the food is b. Convection in the direction indicated by. (Embodiment 3) FIG. 4 shows a rice cooker according to a third embodiment.
It will be described based on. Since a part of the configuration is the same as that of the first embodiment, the description is partially omitted. Reference numeral 31 denotes a pan, 32 denotes a heating coil, and an inner coil 32A disposed on the bottom surface of the pan and an outer coil 32B disposed on the side surface of the pan bottom are connected in series. Inner coil 31A and outer coil 3
An induction coil 33 is provided between 2B. Further, the heating coil and the induction coil
3 strengthens the magnetic coupling. Reference numeral 35 denotes a circuit board for supplying a current for generating an alternating magnetic field to the heating coil 32, and reference numeral 36 denotes a switch device for short-circuiting or opening both ends of the induction coil 33. The operation of the above configuration will be described below. Pot 3
When a cooker (not shown) such as rice water is put into the cooker 1 and a rice cooker is operated, an electric current flows from the circuit board 35 to the first heating coil 32.
Heat. Here, when both ends of the induction coil 23 are opened by the switching device 36, the outer coil 32
Since the input ratio of the alternating magnetic field of A is high, the convection of the object to be cooked in the pan 31 is convection in the direction indicated by a. Next, when the switching device 36 is short-circuited, an induction current flows through the induction coil 33 due to the magnetic flux generated by the heating coil, and the induction coil 33
Then, a magnetic flux that cancels the magnetic flux generated by the heating coil 32 is generated. Since the magnetic flux generated by the induction coil 33 has a greater effect on the outer coil 32B in the vicinity of the induction coil, the magnetic flux received by the pan 31 by the inner coil 32B is relatively reduced, and the convection to the food is b. Convection in the direction indicated by. As described above, the present invention provides a heating coil,
By having an induction coil located in the vicinity of the heating coil and located on a surface facing the pan, and a switch device for short-circuiting and opening both ends of the induction coil, the convection of the food can be varied. In addition, it is possible to provide a rice cooker in which cooking unevenness is significantly improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cutaway longitudinal sectional view of an electric rice cooker according to a first embodiment of the present invention. FIG. 2 is a configuration block diagram of main components of the electric rice cooker. FIG. 4 is a block diagram of an electric rice cooker according to a second embodiment of the present invention. FIG. 4 is a block diagram of an electric rice cooker according to a third embodiment of the present invention. DESCRIPTION OF SYMBOLS 10 Body 11 Coil bases 12, 21, 31 Pots 13, 22, 32 Heating coils 14, 23, 33 Induction coils 17, 25, 35 Circuit boards 18, 26, 36 Switching device

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-113278 (JP, A) JP-A-9-276127 (JP, A) JP-A 8-266401 (JP, A) (58) Field (Int. Cl. ⁷ , DB name) A47J 27/00

Claims (1)

(57) [Claims 1] A body, a pot removably stored in the body, a coil base including a non-metal part surrounding a bottom side surface of the pot, and an outer side of the coil base. A heating coil attached to the pan and heating the pot by electromagnetic induction, an induction coil located near the heating coil and facing the pan, and a switch for short-circuiting and opening both ends of the induction coil An electric rice cooker provided with a device.