JP2011156218A - Electric rice cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric rice cooker by which a mixing body does not hinder when a lid body is open and additionally power loss due to eddy current can be reduced. <P>SOLUTION: The electric rice cooker includes an inner pot 10 for housing a matter to be heated, a rice cooker body 1 in which the inner pot 10 is housed, a mixing blade 40 rotatably arranged in the inner pot 10 and having a magnet 42, a mixing motor arranged outside the inner pot 10 and having a rotary shaft, and an induction coil arranged outside the inner pot 10 and for inductively heating the magnetic body layer 10B of the inner pot 10. A magnet magnetically coupled to the magnet 42 is attached to the rotary shaft of the mixing motor. A part corresponding to an area surrounded by the outer fringe of the rotary blade 40 in the inner pot 10 has a highly thermoconductive member 10A and does not have the magnetic body layer 10B. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric rice cooker.

  Conventionally, as an electric rice cooker, there exists what was disclosed by Unexamined-Japanese-Patent No. 2008-278924 (patent document 1). This electric rice cooker is pivotally attached to the inner pot that contains the rice to be heated, the rice cooker body in which the inner pot is stored, and the upper part of the rice cooker body, and opens and closes the opening of the inner pot. And a lid.

  An upper end portion of a stirring body having a substantially chevron-shaped cross section is rotatably attached to the inner surface of the lid body, and when the lid body is closed, a predetermined gap is formed between the lower end portion of the stirring body and the bottom portion of the inner pot. The gap of is supposed to be vacant. That is, with the lid closed, the stirring body extends from the upper end of the inner space of the inner pot to the vicinity of the lower end of the inner space of the inner pot.

  A rotation drive device is installed in the lid body, and a rotation shaft of the rotation drive device and an upper end portion of the stirring member are connected to each other. Thereby, the said rotation drive device can rotationally drive a stirring body, and can loosen the rice in an inner pot.

  However, in the above-described conventional electric rice cooker, the stirrer extends from the upper end of the inner space of the inner pot to the vicinity of the lower end of the inner space of the inner pot, and the upper end of the stirrer is attached to the inner surface of the lid. There was a problem that the stirrer would get in the way of the cooked rice.

  As an electric rice cooker that solves this problem, the stirrer is separated from the lid, placed on the bottom of the inner pan, and the stirrer does not get caught on the inner surface of the inner pan even if the lid rotates. In addition, a driven drive magnet is attached to the stirrer separated from the lid, and a rotary drive device for rotating the stirrer by magnetic coupling with the driven magnet is provided near the bottom of the inner pot. The arranged electric rice cooker can be considered.

  However, in an electric rice cooker using induction heating, the inner surface of the inner pot is generally composed of a non-magnetic material layer, and the outer surface of the inner pot is composed of a magnetic material layer. The lower rotary drive device below receives a large amount of heat from the magnetic layer on the outer surface of the inner pot. As a result, there arises a new problem that the temperature of the rotary drive device becomes abnormally high.

JP 2008-278924 A (FIG. 1)

  Then, the subject of this invention is providing the electric rice cooker which can prevent that the temperature of a rotation drive device becomes abnormally high while a stirring body does not become obstructive at the time of opening of a cover body.

In order to solve the above problems, the electric rice cooker of the present invention is
An inner pot that contains the object to be heated and has a portion in which the nonmagnetic layer and the magnetic layer are stacked;
A rice cooker body in which the inner pot is stored;
A lid that can be freely opened and closed at the top of the rice cooker body, and can be closed to cover the inner pot,
A stirring body that is separated from the lid and is rotatably arranged in the inner pot, and has a driven-side magnet;
A rotation driving device arranged outside the inner pot and driving the stirring body to rotate;
An induction heating unit arranged outside the inner pot, for induction heating the magnetic layer of the inner pot,
The rotational driving device includes a rotating magnetic field generating device that magnetically couples with the driven-side magnet and generates a rotating magnetic field for rotationally driving the agitator.
The portion corresponding to the rotating magnetic field generator in the inner pot is characterized in that the nonmagnetic layer is present and the magnetic layer is absent.

  According to the above configuration, the stirring body is separated from the lid body, and therefore does not get in the way when the lid body is opened.

  Further, the portion corresponding to the rotating magnetic field generator in the inner pot has a non-magnetic layer and no magnetic layer, so even if the magnetic layer of the inner pot is heated by induction, the rotating magnetic field generator The temperature rise in the corresponding part is relatively small. Therefore, since the amount of heat transmitted from the inner pot to the rotating magnetic field generator is reduced, it is possible to prevent the temperature of the rotating drive device from becoming abnormally high.

  Further, the portion corresponding to the rotating magnetic field generator in the inner pot is a non-magnetic material layer and does not have a magnetic material layer, so that it is received from the magnetic material layer in the magnetic coupling by the driven magnet and the rotating magnetic field generator. The adverse effect is reduced. Therefore, the magnetic coupling can be strengthened and the coupling torque can be increased.

In the electric rice cooker of one embodiment,
In the inner pot, the portion corresponding to the region surrounded by the rotation trajectory of the driven magnet has the non-magnetic layer and does not have the magnetic layer.

  According to the above embodiment, the portion corresponding to the region surrounded by the rotation trajectory of the driven magnet in the inner pot has a nonmagnetic layer and no magnetic layer. The amount of heat transferred to the magnetic field becomes smaller, and the adverse effect of the magnetic layer on the magnetic coupling torque becomes smaller.

In the electric rice cooker of one embodiment,
In the inner pot, the portion corresponding to the region surrounded by the outer edge of the stirring member has the nonmagnetic layer and does not have the magnetic layer.

  According to the above embodiment, the portion corresponding to the region surrounded by the outer edge of the stirring member in the inner pot has a nonmagnetic layer and no magnetic layer, so the amount of heat transferred from the inner pot to the rotating magnetic field generator. Is further reduced, and the adverse effect of the magnetic layer on the magnetic coupling torque is further reduced.

In the electric rice cooker of one embodiment,
The rotating magnetic field generator includes a rotating shaft and a driving magnet attached to the rotating shaft.

  According to the above embodiment, the rotating magnetic field generator has a rotating shaft and a drive-side magnet attached to the rotating shaft, so that the rotating magnetic field can be easily generated by rotating the driving-side magnet together with the rotating shaft. Can be generated.

  According to the electric rice cooker of the present invention, the lid that is attached to the top of the rice cooker main body so as to be opened and closed and can be closed so as to cover the inner pan, and the lid are separated, and the inner pan And a stirring body that is rotatably arranged inside, the stirring body does not get in the way when the lid is opened.

  In addition, since the portion corresponding to the rotating magnetic field generator in the inner pot has a non-magnetic layer and does not have a magnetic layer, even if the magnetic layer of the inner pan is induction-heated, the temperature rise in that portion is Relatively small. Therefore, since the amount of heat received from the inner pan by the rotating magnetic field generator is reduced, it is possible to prevent the temperature of the rotary drive device from becoming abnormally high.

  Further, the portion corresponding to the rotating magnetic field generator in the inner pot is a non-magnetic material layer and does not have a magnetic material layer, so that it is received from the magnetic material layer in the magnetic coupling by the driven magnet and the rotating magnetic field generator. The adverse effect is reduced. Therefore, the magnetic coupling can be strengthened and the coupling torque can be increased.

FIG. 1 is a perspective view of an electric rice cooker according to an embodiment of the present invention. FIG. 2 is a perspective view of the electric rice cooker with the lid opened. FIG. 3 is a vertical end view of the electric rice cooker as seen from line III-III in FIG. FIG. 4 is a vertical end view of the electric rice cooker as seen from line IV-IV in FIG. FIG. 5 is an end view of the lower part of the inner pot and the stirring blades of the electric rice cooker. FIG. 6 is a control block diagram of the electric rice cooker. FIG. 7 is an end view for explaining a modification of the inner pot of the electric rice cooker. FIG. 8 is an end view for explaining a modification of the inner pot of the electric rice cooker.

  Hereinafter, the electric rice cooker of this invention is demonstrated in detail by embodiment of illustration.

  FIG. 1 is a perspective view of an electric rice cooker according to an embodiment of the present invention as viewed obliquely from above.

  The electric rice cooker includes a rice cooker body 1 and a lid 2 attached to the rice cooker body 1 so as to be freely opened and closed. The rice cooker main body 1 includes a display operation unit 3 provided on the front side, a hook button 4 provided on the front side and the upper side, a main body handle 5 rotatably attached to the rear side, and a rear side and a lower side. And a power cord 6 connected to the side. A steam port 2 a is provided on the rear surface side of the lid 2. The display operation unit 3 includes a liquid crystal display and a plurality of operation buttons, and can display and operate a cooking menu, cooking status, and the like. The lid body 2 is closed in a releasably locked state by a latch mechanism (not shown) provided in the rice cooker body 1, and the latch mechanism is unlocked by pressing the hook button 4. Then, the lid 2 is opened by the urging force of the spring 26 (shown in FIG. 3).

  FIG. 2 is a perspective view of the electric rice cooker with the lid 2 opened.

  The lid body 2 has an outer lid 21 and an inner lid 22, and the rice cooker body is rotatable about a hinge shaft 20 (shown in FIG. 3) provided on the upper side and the rear surface side of the rice cooker body 1. 1 is attached. Moreover, in the rice cooker main body 1, the inner pot 10 which accommodates to-be-heated material (for example, rice) can be accommodated.

  The upper end of the inner pot 10 is open, and the shape of the opening as viewed from above is substantially circular. In addition, an annular flange portion 10 a is provided on the edge of the opening at the upper end of the inner pot 10. And the inner pot handle 11, 11 made of heat-resistant resin is attached to the flange portion 10a of the inner pot 10 so as to face each other in the radial direction. Moreover, the recessed part 12a (only one of the right side is shown in FIG. 2) is provided in two places on the right and left of the upper surface of the rice cooker main body 1, respectively.

  FIG. 3 is a vertical end view of the electric rice cooker as seen from line III-III in FIG.

  The rice cooker body 1 includes an outer case 12 and an inner case 13 that is disposed in the outer case 12 and in which the inner pot 10 is accommodated. The inner case 13 is formed of a material having heat resistance and electrical insulation.

  A power supply unit 14 including a power supply circuit, an inverter circuit, and the like is disposed on the rear side (right side in FIG. 3) of the space between the outer case 12 and the inner case 13, and the power supply unit is provided below the power supply unit 14. A cooling fan 15 for cooling 14 and the like is disposed. Further, a cord reel 7 for winding the power cord 6 is disposed below the cooling fan 15 and on the bottom of the outer case 12.

  The inner pot 10 includes a flange portion 10a, a peripheral wall portion 10b extending vertically downward from an inner peripheral edge portion of the flange portion 10a, and an inclined portion 10c extending obliquely downward in a vertical direction from the lower end of the peripheral wall portion 10b. An annular bottom portion 10d extending in the horizontal direction and continuing to the lower end of the inclined portion 10c, and a ridged cylindrical convex portion 10e projecting vertically upward, that is, inward, continuing to the inner peripheral edge portion of the bottom portion 10d. Yes. A disc-shaped stirring blade 40 separated from the lid 2 is rotatably fitted to the convex portion 10 e of the inner pot 10. And the recessed part is formed in the part corresponding to the convex part 10e in the outer surface of the inner pot 10. The concave portion on the outer surface of the inner pot 10 is formed with the formation of the convex portion 10 e of the inner pot 10. The stirring blade 40 is an example of a stirring body.

  The stirring blade 40 includes a holding unit 60 and a disk unit 70 that is detachably attached to the holding unit 60. The holding unit 60 holds the annular yoke 41 and a plurality of magnets 42 arranged at equal intervals in the circumferential direction inside the yoke 41. The magnet 42 is an example of a driven side magnet.

  Moreover, the opening part 13a is provided in the part located in the said inner case 13 below the convex part 10e of the inner pot 10. As shown in FIG. Further, a stirring motor 17 having a rotating shaft 17a is disposed below the opening 13a. The rotating shaft 17 a of the stirring motor 17 is connected to the shaft portion 82 of the rotor 80. The stirring motor 17 and the rotor 80 are an example of a rotational drive device. The rotor 80 and the rotating shaft 17a are an example of a rotating magnetic field generator.

  The rotor 80 has a plurality of magnets 18 arranged in the circumferential direction and at equal intervals. The plurality of magnets 18 are accommodated in the recesses on the outer surface of the inner pot 10, and magnetically couple with the plurality of magnets 42 of the stirring blade 40 in the radial direction of the rotating shaft 17 a of the stirring motor 17. Thus, when the agitating motor 17 rotates the rotor 80, the agitating blade 40 can also be rotated. The magnet 18 is an example of a drive side magnet.

  Note that reference numeral 90 in FIG. 3 denotes a cover that covers the rotor 80.

  Further, on the front side (the left side in FIG. 3) of the space between the outer case 12 and the inner case 13, the display / operation unit 3 (shown in FIGS. 1 and 2), the inverter circuit of the power supply unit 14, and the cooling fan. 15 and a control unit 30 for controlling the stirring motor 17 and the like are arranged.

  An induction coil 31 for induction heating the magnetic layer 10B (shown in FIG. 5) of the inner pot 10 is disposed below the inner case 13 in the rice cooker body 1. The induction coil 31 is bonded to the inner surface of the inner case 13 (surface opposite to the surface facing the inner pot 10) with a heat-resistant resin or the like. Further, a ferrite member 39 and the like for preventing leakage magnetic flux of the induction coil 31 are disposed below the induction coil 31. Further, a bottom temperature sensor 33 penetrating the inner case 13 is also disposed below the inner case 13. The bottom temperature sensor 33 detects the temperature of the inner pot 10 by contacting the tip of the inclined portion 10 c of the inner pot 10 housed in the inner case 13. The induction coil 31 is an example of an induction heating unit.

  A horizontal heater 32 is disposed in the rice cooker body 1. The horizontal heater 32 is provided along the circumferential direction so as to surround the upper side portion of the inner case 13. A lid heater 38 (shown in FIG. 4) and a lid temperature sensor 34 (shown in FIG. 6) are arranged in the lid 2.

  The induction coil 31, the lateral heater 32, and the lid heater 38 constitute a heating unit that heats the entire inner pot 10.

  The lid body 2 includes an outer lid 21 that is rotatably supported by the rice cooker body 1 and an inner lid 22 that is detachably attached to the side of the outer lid 21 that faces the inner pot 10. Yes. An annular heat-resistant rubber packing 23 is detachably attached to the outer periphery of the inner lid 22. When the lid body 2 is closed, the packing 23 is in close contact with the upper surface of the flange portion 10 a of the inner pot 10 to seal between the inner pot 10 and the inner lid 22.

  Note that reference numeral 24 in FIG. 3 denotes a steam hole provided in the inner lid 22.

  FIG. 4 is a vertical end view of the electric rice cooker as seen from line IV-IV in FIG.

  When the inner pot handles 11, 11 of the inner pot 10 are fitted into the recesses 12 a, 12 a provided on the left and right of the upper surface of the outer case 12 of the rice cooker body 1, the inner pot 10 is attached to the rice cooker body 1. Positioned against.

  A magnet 50 is embedded in the inner pot handle 11. In addition, a reed switch 25 that is turned on by the magnetism of the magnet 50 when the lid 2 is closed is attached to a portion of the outer lid 21 that is positioned on the magnet 50. A magnet 50 is embedded in each of the inner pot handles 11 and 11.

  FIG. 5 is a view showing an end face obtained by cutting the lower portion of the inner pot 10 and the stirring blade 40.

  The inner pot 10 includes, for example, a high heat conductive member 10A such as aluminum and a magnetic layer 10B such as stainless steel that improves heating efficiency. While the high heat conductive member 10A is molded by pressing or casting, the magnetic layer 10B is formed only on a predetermined portion of the outer surface of the high heat conductive member 10A using, for example, a spraying technique. In addition, the inner surface of the high thermal conductive member 10A is coated with a fluororesin for preventing adhesion of an object to be heated. The high heat conductive member 10A is an example of a nonmagnetic layer.

  The magnetic layer 10B covers only the entire outer surface of the high thermal conductivity member 10A in the inclined portion 10c and the outer peripheral edge portion of the outer surface of the high thermal conductivity member 10A in the bottom portion 10d. For this reason, most of the bottom portion 10d and all of the convex portions 10e do not have the magnetic layer 10B. That is, the portion corresponding to the region surrounded by the outer edge of the stirring blade 40 in the inner pot 10 has the high heat conductive member 10A and does not have the magnetic layer 10B.

  FIG. 6 is a control block diagram of the electric rice cooker.

  The control unit 30 includes a microcomputer, an input / output circuit, and the like, and is based on an operation signal from the display operation unit 3, a signal from the reed switch 25, the bottom temperature sensor 33, the lid temperature sensor 34, or the like. 3. Control the stirring motor 17, cooling fan 15, induction coil inverter circuit 35, side heater circuit 36 and lid heater circuit 37. The induction coil inverter circuit 35 causes the induction coil 31 to generate an alternating magnetic field. The induction coil inverter circuit 35 is an example of an induction heating unit.

  The induction coil inverter circuit 35, the lateral heater circuit 36, and the lid heater circuit 37 are included in the power supply unit 14 (shown in FIG. 3).

  According to the electric rice cooker having the above configuration, as shown in FIGS. 3 and 4, the magnet 42 of the stirring blade 40 is magnetically coupled to the magnet 18 of the rotor 80, and the shaft portion 82 of the rotor 80 is rotated by the stirring motor 17. It is connected to the shaft 17a. Therefore, although the stirring motor 17 and the rotor 80 are arranged outside the inner pot 10, the stirring blade 40 can be driven to rotate by rotating the rotating shaft 17a of the stirring motor 17. That is, the stirring blade 40 can be rotationally driven via the magnetic coupling.

  Further, since the stirring blade 40 is separated from the lid 2, the stirring blade 40 does not get in the way when the lid 2 is opened, and the lid 2 can be completely opened.

  Further, as shown in FIG. 5, the portion corresponding to the region surrounded by the outer edge of the stirring blade 40 in the inner pot 10 has the high heat conduction member 10 </ b> A and does not have the magnetic layer 10 </ b> B. Even if the body layer 10B is induction-heated, the temperature rise in the portion corresponding to the region surrounded by the outer edge of the stirring blade 40 is relatively small. In other words, a wide area around the rotor 80 and the cover 90 in the inner pot 10 is cooler than the other parts. Therefore, since the amount of heat received by the rotor 80 and the cover 90 from the inner pot 10 is very small, it is possible to reliably prevent the temperature of the stirring motor 17, the rotor 80, and the cover 90 from becoming abnormally high.

  Further, the portion corresponding to the region surrounded by the outer edge of the stirring blade 40 in the inner pot 10 has the high heat conductive member 10A and does not have the magnetic layer 10B. That is, the magnetic layer 10 </ b> B is not interposed between the magnet 18 and the magnet 42. Thereby, the bad influence received from the magnetic body layer 10B in the magnetic coupling by the magnet 18 and the magnet 42 becomes small. Therefore, the magnetic coupling can be strengthened and the coupling torque can be increased.

  In the said embodiment, it may replace with the inner pot 10 and the inner pot 210 shown in FIG. 7 or the inner pot 310 shown in FIG. 8 may be used.

  Like the inner pot 10, the inner pot 210 has an inclined portion 210c, a bottom portion 210d, and a convex portion 210e. The entire outer surface of the high heat conductive member 10A in the inclined portion 210c, the outer peripheral edge portion of the outer surface of the high heat conductive member 10A in the bottom portion 210d, and the central portion adjacent thereto are covered with the magnetic layer 10C. The magnetic layer 10C does not cover the inner peripheral edge portion of the outer surface of the high heat conductive member 10A in the bottom portion 210d and the entire outer surface of the high heat conductive member 10A in the convex portion 210e. That is, the portion corresponding to the region surrounded by the rotation trajectory of the magnet 42 in the inner pot 210 has the high heat conductive member 10A and does not have the magnetic layer 10C.

  Similar to the inner pot 10, the inner pot 310 has an inclined portion 310c, a bottom portion 310d, and a convex portion 310e. The entire outer surface of the high thermal conductivity member 10A in the inclined portion 310c and the entire outer surface of the high thermal conductivity member 10A in the bottom portion 310d are covered with the magnetic layer 10D. The magnetic layer 10D does not cover the entire outer surface of the high thermal conductive member 10A in the convex portion 310e. That is, the portion corresponding to the rotor 80 and the rotating shaft 17a in the inner pot 310 has the high heat conductive member 10A and does not have the magnetic layer 10D.

  Even if such inner pots 210 and 310 are used, the effect of suppressing the temperature increase of the agitating motor 17, the rotor 80 and the cover 90 and the effect of improving the coupling torque can be obtained.

  7 and 8, the same components as those shown in FIG. 5 are denoted by the same reference numerals as those of the components in FIG.

  In the embodiment described above, the magnet 42 of the stirring blade 40 is magnetically coupled in the radial direction of the magnet 18 of the rotor 80 and the rotary shaft 17a. However, the magnetic cup in the axial direction of the magnet 18 of the rotor 80 and the rotary shaft 17a is used. You may make it ring. When the magnet 42 of the stirring blade 40 and the magnet 18 of the rotor 80 are magnetically coupled in the axial direction of the rotating shaft 17a, an inner pot having no convex portion such as the convex portion 10e may be used.

  In the above embodiment, instead of the stirring motor 17 and the rotor 80, for example, a stator yoke of a synchronous motor, a plurality of coils wound around the stator yoke, and a rotating magnetic field are generated in the plurality of coils. An AC power source may be used. By generating a rotating magnetic field by the stator yoke and the AC power source, the magnetically coupled stirring blade 40 can be rotationally driven. In short, any device that can generate a rotating magnetic field may be housed in a recess on the outer surface of the bottom of the inner pot 10.

  Although specific embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Rice cooker main body 2 ... Lid 2a ... Steam port 3 ... Display operation part 4 ... Hook button 5 ... Main body handle 6 ... Power cord 7 ... Cord reel 10,210,310 ... Inner pan 10A ... High heat conductive member 10B ... Magnetic Body layer 10a ... Flange part 10e ... Convex part 11 ... Inner pan handle 12 ... Outer case 12a ... Concave part 13 ... Inner case 14 ... Power supply part 15 ... Cooling fan 16 ... Rotor 17 ... Stirring motor 18 ... Magnet 20 ... Hinge shaft 21 ... Outer lid 22 ... Inner lid 23 ... Packing 24 ... Steam hole 25 ... Reed switch 26 ... Spring 30 ... Control unit 31 ... Induction coil 32 ... Transverse heater 33 ... Bottom temperature sensor 34 ... Lid temperature sensor 35 ... Inverter circuit 36 for induction coil ... Circuit for lateral heater 37 ... Circuit for lid heater 38 ... Cover heater 39 ... Ferrite member 40 ... Stirrer blade 41 ... Yoke 42 ... Magnet 5 ... magnet

Claims (4)

An inner pot that contains the object to be heated and has a portion in which the nonmagnetic layer and the magnetic layer are stacked;
A rice cooker body in which the inner pot is stored;
A lid that can be freely opened and closed at the top of the rice cooker body, and can be closed to cover the inner pot,
A stirring body that is separated from the lid and is rotatably arranged in the inner pot, and has a driven-side magnet;
A rotation driving device arranged outside the inner pot and driving the stirring body to rotate;
An induction heating unit arranged outside the inner pot, for induction heating the magnetic layer of the inner pot,
The rotational driving device includes a rotating magnetic field generating device that magnetically couples with the driven-side magnet and generates a rotating magnetic field for rotationally driving the agitator.
The portion corresponding to the rotating magnetic field generator in the inner pot has the non-magnetic material layer and does not have the magnetic material layer. In the electric rice cooker according to claim 1,
The electric rice cooker characterized in that the portion corresponding to the region surrounded by the rotation locus of the driven magnet in the inner pot has the non-magnetic layer and does not have the magnetic layer. In the electric rice cooker according to claim 1 or 2,
In the inner pot, the portion corresponding to the region surrounded by the outer edge of the stirrer is provided with the non-magnetic layer, and does not have the magnetic layer. In the electric rice cooker as described in any one of Claim 1 to 3,
The rotating magnetic field generator includes a rotating shaft and a drive-side magnet attached to the rotating shaft.

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