CN1248632C - Electric cooker - Google Patents

Abstract

The electric rice cooker of the present invention comprises: a main body, a container detachably accommodated in the main body, and a cover body that covers the main body freely. A heating coil on the protective frame for inductively heating the container, and one or more conductive loop wires arranged outside and/or below the heating coil. The present invention can effectively reduce the magnetic field (magnetic flux) leaked from the electric rice cooker to the outside, and provide a small, light and cheap electric rice cooker.

Description

rice cooker

technical field

The present invention relates to an electric rice cooker for general household or business use.

Background technique

In recent years, electric rice cookers utilizing electromagnetic induction heating have flooded the market. A conventional example of an electric rice cooker is disclosed in Japanese Patent Application Publication No. 4-36009. Fig. 13 is a schematic sectional view of a conventional rice cooker. In FIG. 13 , 9001 is a substantially cylindrical body with an open upper surface, and is covered with an openable and closable cover 9012 . The inner pot 9002 is detachably accommodated inside the main body 9001 . The inner pot 9002 is made of magnetic materials such as stainless steel and iron. The protective frame 9003 is a housing portion of the inner pot 9002, and is formed of a non-metallic material into a cylindrical shape with a bottom. A heating coil 9013 for inductively heating the inner pot 9002 is provided outside the protective frame 9003 . The heating coil 9013 is composed of an inner coil 9005 provided outside the bottom surface of the protective frame 9003 and an outer coil 9004 provided on the outer periphery thereof. Furthermore, ferrite 9006 is provided outside the heating coil 9013, thereby performing magnetic shielding to the outside (reducing the magnetic flux leaked from the rice cooker to the outside). 9008 is a temperature sensor that measures the temperature of the inner pot 9002. 9009 is a control board that supplies high-frequency power to the heating coil 9013 .

9007 is an anti-magnetic plate made of conductive materials (such as aluminum). The antimagnetic plate 9007 is provided on the outer peripheral side of the heating coil 9013 . An eddy current that cancels the magnetic field passing through the magnetic shield 9007 is generated in the magnetic shield 9007 . The magnetic shield 9007 reduces the magnetic field (magnetic flux) leaked to the outside of the rice cooker, thereby preventing the temperature of the main body 9001 or components outside the main body 9001 from rising due to the magnetic flux leaked to the outside of the heating coil 9013.

However, the rice cooker of the conventional example has a built-in large cylindrical aluminum magnetic shielding plate, so the main body is larger than the inner pot of the rice cooker, and there are problems of poor handling and installation. There is also the problem that the weight of the electric rice cooker is increased and the cost is increased by using the aluminum antimagnetic plate. In addition, the magnetic shield sometimes cannot be arranged due to the difference in the arrangement of the substrate and the size of the body. It is necessary to change the shape of the antimagnetic plate according to the type and capacity of the rice cooker, and the antimagnetic plate cannot be used universally.

The present invention solves the above-mentioned problems, and an object of the present invention is to provide a compact, lightweight, and inexpensive rice cooker capable of effectively reducing magnetic fields (magnetic fluxes) leaking to the outside of the rice cooker.

Contents of the invention

In order to solve the above-mentioned problems, the present invention has the following structures. The electric rice cooker according to the technical solution 1 of the present invention includes: a main body, a container detachably accommodated in the main body, and a cover body that covers the main body freely, the main body has a protective frame for accommodating the container, A heating coil installed on the protective frame to inductively heat the container, and one or more conductive loop wires arranged outside and/or below the heating coil.

The ring wire is cheaper and lighter than the conventional aluminum antimagnetic board, and can be installed in a small space. In the electric rice cooker of the conventional example, the large fixed-shaped antimagnetic plate greatly limits the shape of the housing of the main body. The thin and soft ring wire has almost no restrictions on the freedom of the shape of the main body's casing. The magnetic field generated by the current flowing in the loop cancels the magnetic field in and around the loop. One or more loop wires installed in appropriate places have approximately the same antimagnetic effect as the aluminum antimagnetic plate of the conventional example. It is best to set up multiple loops.

The present invention can effectively reduce the magnetic field (magnetic flux) leaked from the electric rice cooker to the outside, and has the effect of realizing a small, lightweight and cheap electric rice cooker. The present invention can realize an electric rice cooker that is easy to carry and has good installability.

"Loop line" means a line that electrically forms a closed loop. The toroidal wire is, for example, concentrically or helically wound into a toroidal wire with one or more turns. The loop line is preferably one or more 1-turn closed loops. The thread may be a single thread or a twisted thread. The wire may be a bare wire or a covered wire.

"The loop line provided outside the heating coil" means that the vertical projection plane of the heating coil is included in the surface defined by the outer circumference of the loop line (for example, in a loop line wound helically in multiple turns, the outermost line is the outer circumference. plane) in the vertical projection plane.

"The loop line arranged below the heating coil" means: the lower end of the horizontal projection plane of the loop line (for example, when multiple loop lines are arranged at different heights, the lower end of the horizontal projection plane of the lowermost loop line) is lower than the horizontal projection plane of the heating coil. The lower end of the projection surface is low.

One loop wire may be provided outside and below the heating coil.

In the rice cooker according to another aspect of the present invention, the heating coil includes a first heating coil whose outermost peripheral part is arranged at a higher position than the innermost peripheral part, and at least one of the loop wires is provided on the first heating coil. Near the outermost part of the first heating coil, at a position outside and higher than the outermost part, or near the innermost part of the first heating coil, inside and lower than the innermost part position.

The magnetic flux emitted by the first heating coil to the outside is located near the outermost peripheral portion of the first heating coil, at a position higher outside and higher than the outermost peripheral portion, and at a position near the innermost peripheral portion of the first heating coil, which is higher than the innermost peripheral portion. It is largest at the inner and lower position of the peripheral part. Here, a good anti-magnetic effect can be obtained by setting the loop line. The invention can realize the electric rice cooker with better antimagnetic effect. It is preferable to arrange the loop wires at a position near the outermost peripheral portion of the first heating coil, which is further outside and higher than the outermost peripheral portion, and near the innermost peripheral portion of the first heating coil, which is further inside and higher than the innermost peripheral portion. low position.

In the rice cooker according to still another aspect of the present invention, it is installed near the outermost peripheral portion of the first heating coil at a position outside and higher than the outermost peripheral portion or at the outermost peripheral portion of the first heating coil. The sum of the cross-sectional areas of the conductors of the loop wires near the inner peripheral portion at a position further inside and lower than the innermost peripheral portion is larger than that of the loop wires provided at other positions.

By increasing the cross-sectional area of the conductor of the loop wire, a large current flows through the loop wire, thereby generating a larger repulsive magnetic field. The invention can realize the electric rice cooker with better antimagnetic effect.

"The sum of the cross-sectional areas of the conductors of the loop wire is large" means, for example, that the diameter of the loop wire is larger than that of the loop wires at other positions. The loop wires may be arranged one by one at another position, and a plurality of loop wires of the same diameter may be arranged in a bundle near the outermost peripheral portion of the first heating coil at a position higher outside and higher than the outermost peripheral portion.

In the rice cooker according to still another technical solution of the present invention, a control board or an operation board for supplying high-frequency power to the heating coil is further arranged on the outer peripheral side of the protective frame, and at least one of the loop wires is connected to It is arranged on the outside of the control substrate.

By setting the loop wire outside the control substrate, the loop wire cancels the magnetic flux generated by the electronic components (such as choke coil) on the control substrate, reducing the magnetic flux leaked from the rice cooker to the outside. The invention can realize the electric rice cooker with better antimagnetic effect.

In the rice cooker according to still another aspect of the present invention, a temperature sensor for detecting the temperature of the container is provided inside the innermost circumference of the heating coil, and an output signal from the temperature sensor is transmitted to the control board. The temperature sensor signal line is arranged approximately perpendicular to the loop line.

By making the temperature sensor signal line substantially perpendicular to the antimagnetic loop line, it is possible to prevent the magnetic field generated by the antimagnetic loop line from entering the temperature sensor signal line as noise. The temperature sensor signal line transmits an accurate temperature sensor signal with less noise. The invention can effectively reduce the magnetic field (magnetic flux) leaked from the electric rice cooker to the outside, can detect the temperature of the container with high precision, and realizes the electric rice cooker that controls the heating coil.

The electric rice cooker of another technical solution of the present invention also has one or more ferrite members formed of high-permeability magnetic materials on the outside of the heating coil. The longitudinal direction of the winding wires of the coil is substantially perpendicular, and at least one of the loop wires is provided on the upper side near the upper end of the ferrite member or on the lower side near the lower end of the ferrite member. .

The magnetic field (magnetic flux) is particularly concentrated around a ferrite member with little magnetic resistance. By disposing the loop wire on the upper side near the upper end of the ferrite member or on the lower side near the lower end of the ferrite member, a large current flows through the loop wire, and the loop wire effectively generates a repulsive magnetic field. The invention can realize the electric rice cooker with better antimagnetic effect. Preferably, the loop wires are respectively provided on the upper side near the upper end of the ferrite member and on the lower side near the lower end of the ferrite member.

The rice cooker according to another technical solution of the present invention further has a loop wire installation member fixed to the protective frame or formed integrally with the protection frame, at least one of the loop wires is clamped in the groove formed on the loop wire installation member .

The invention can realize the electric rice cooker which has good antimagnetic effect, is easy to fix the loop wire with few steps, and is easy to manufacture.

"Clamped in the groove" means that the loop wire is clamped so as not to fall from the groove at least due to its own weight. Even if the loop wire is further bonded to the loop wire mounting member with an adhesive, as long as the loop wire is clamped so as not to fall from the groove due to its own weight at least, it falls within the technical scope of the present invention. Even in the case of using an adhesive, as long as the loop wire is clamped so as not to fall from the groove due to its own weight at least, it is possible to obtain the effect of easy operation in the bonding process at the factory.

The number of loop installation components can be arbitrary. Typically, a plurality of loop installation members are installed on the outer periphery of the protective frame.

In the electric rice cooker according to still another technical solution of the present invention, the protective frame is integrally formed with at least one of the loop wires.

The invention has good antimagnetic effect, can cancel or greatly reduce the process of fixing loop wires, and is an electric rice cooker with few manufacturing processes and easy manufacture.

It is also possible to form the loop wire with bare wires by covering most of the loop wire with the resin of the protective frame.

The rice cooker according to still another technical solution of the present invention is further provided with a ferrite table that accommodates the ferrite member and has a groove, and is fixed to the protective frame, and at least one of the loop wires is clamped on the ferrite In the groove of the body platform.

In the present invention, the ferrite stand can be used both for fixing the ferrite member and for fixing the loop wire. The invention can realize an inexpensive electric rice cooker which does not increase the number of parts and has good antimagnetic effect.

A rice cooker according to still another aspect of the present invention further includes a second protective frame that accommodates part or all of the protective frame, and the second protective frame is integrally formed with at least one of the loop wires.

The invention can realize an electric rice cooker that does not increase the number of parts, is easy to assemble and has a good antimagnetic effect.

In the electric rice cooker according to still another technical solution of the present invention, the loop wire is covered with a heat-resistant covering layer.

A highly reliable rice cooker can be provided by using a covered wire having a heat-resistant coating (for example, a Junflon wire (registered trademark)) as a loop wire.

The electric rice cooker according to still another technical solution of the present invention further has a disconnection detection part for detecting the disconnection of the loop wire, and when the disconnection detection part detects that the loop wire is disconnected, it stops heating the coil or reduces its temperature. output, and/or indicate that the loop is broken.

The present invention can realize a safe electric rice cooker with high reliability.

In the rice cooker according to still another aspect of the present invention, the disconnection detection unit detects a disconnection of the loop wire based on a change in the operating frequency of the inverter.

When the loop line is disconnected, the load of the inverter driving the heating coil at the resonance frequency changes, and the operating frequency (resonance frequency) of the inverter changes. By detecting the change in the operating frequency, it is possible to detect the disconnection of the loop without using a special disconnection sensor. The invention can realize a highly reliable, safe and cheap electric rice cooker.

The rice cooker according to still another aspect of the present invention further includes a reel for winding a power cord, and the reel is provided outside the looped wire.

The noise output by electrical equipment through the power line must be suppressed below the specified level. The structure of the invention can suppress the noise output by the electric rice cooker through the power line.

The novel features of the present invention are the contents described in the claims. Through the accompanying drawings and the following detailed description, it is believed that the structure, content and other objectives and features of the present invention can be better understood and evaluated.

Description of drawings

Fig. 1 is a schematic sectional view showing a rice cooker according to Example 1 of the present invention.

Fig. 2 is a schematic back view showing the rice cooker according to Embodiment 1 of the present invention.

Fig. 3 is a partial cross-sectional view showing the rice cooker according to Example 1 of the present invention.

Fig. 4 is a perspective view showing main parts of the rice cooker according to Example 1 of the present invention.

Fig. 5 is a diagram showing a configuration of a disconnection detection unit of the rice cooker according to Example 1 of the present invention.

Fig. 6 is a schematic partial sectional view of a rice cooker used in an experiment on which the present invention is based.

Fig. 7 is a schematic back view showing an electric rice cooker according to Example 2 of the present invention.

Fig. 8 is a partial cross-sectional view showing a rice cooker according to Example 3 of the present invention.

Fig. 9 is a partial cross-sectional view showing a rice cooker according to Example 4 of the present invention.

Fig. 10 is a partial cross-sectional view showing a rice cooker according to Embodiment 5 of the present invention.

Fig. 11 is a perspective view showing a ferrite base and antimagnetic loop wire mounting member of an electric rice cooker according to Embodiment 6 of the present invention.

Fig. 12 is a schematic sectional view showing a rice cooker according to Embodiment 7 of the present invention.

Fig. 13 is a schematic sectional view showing a conventional rice cooker.

Please note here that part or all of the drawings are described in schematic representation for the purpose of illustration, and do not necessarily faithfully reflect the actual relative sizes and positions of the components shown.

Detailed ways

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention are described below with reference to the accompanying drawings.

Example 1

The rice cooker of Example 1 of this invention is demonstrated using FIGS. 1-6 and Table 1. FIG.

Fig. 1 and Fig. 2 are a schematic cross-sectional view and an inside view of an electric rice cooker according to Embodiment 1 of the present invention. 101 is a substantially cylindrical body with an open upper surface, and is covered with an openable and closable cover 112 . Inside the main body 101 is housed an inner pot (container) 102 which is a detachable container. The inner pot 102 is made of magnetic materials such as stainless steel and iron. The main body 101 has a protective frame 103, a ferrite body 106, an antimagnetic ring wire 107, a temperature sensor 108, a control substrate 109, a radiator 110, a heating coil 113, a temperature fuse 114, a temperature sensor signal line 115, and a reel 111 for a commercial power line And power cord 116.

The protective frame 103 is an accommodating part of the inner pot 102, and is formed in a bottomed cylindrical shape from a non-metallic material such as resin. The heating coil 113 for inductively heating the inner pot 102 is buried outside the protective frame 103 with its outer surface exposed. The heating coil 113 is composed of an outer coil 104 arranged outside the bottom surface of the protective frame 103 and an inner coil 105 arranged on the outer periphery.

Six ferrites 106 are arranged radially outward of the heating coil 113 , and the ferrites 106 are arranged substantially perpendicular to the winding length direction of the heating coil 113 . The ferrite 106 is formed of a highly permeable magnetic material. The ferrite 106 prevents the magnetic field caused by the heating coil 113 from leaking to the outside of the body 101 while promoting induction heating of the inner pot 102 . Only three ferrites cover the outer coil 104 because the inner coil 104 has a smaller skin area than the outer coil 105 and the height of the main body 101 is lower.

108 is a temperature sensor for detecting the temperature of the inner pot 102 . 114 is a thermal fuse. The temperature sensor 108 and the thermal fuse 114 are arranged inside the innermost circumference of the inner coil 105 . Lead wires connecting the temperature sensor 108, the thermal fuse 114, and the control board 109, that is, the temperature sensor signal line 115 (including the temperature sensor signal line and the thermal fuse signal line for transmitting the respective output signals of the temperature sensor 108 and the thermal fuse 114 to the control board 109 Line), arranged to be approximately perpendicular to the antimagnetic loop line 107. 111 and 116 are reels and power leads for accommodating commercial power cords. In order to avoid the noise caused by the heating coil 113 , the reel 111 of the power cord and the power wire 116 are arranged outside the antimagnetic ring 107 . The power wire 116 connects the power wire and the control board 109 . The control board 109 supplies the heating coil 113 with high-frequency power for generating an alternating magnetic field from a commercial power supply, outputs from the temperature sensor 108 and the thermal fuse 114 , and input signals from an operation board (not shown). The operation board receives input signals from an operation panel (not shown) arranged outside the main body. The control board 109 may also serve as an operation board. 110 is a heat sink, which is mounted on the control board 109 and cools the switching elements (semiconductors) that control the current flowing to the heating coil 113 .

107 is an antimagnetic loop. In the embodiment example, six antimagnetic loop wires 107 are arranged concentrically. Each antimagnetic loop wire 107 is a closed loop with one turn. In Fig. 1, in order to make it easier to see the drawings, only two anti-magnetic loop lines are shown. Fig. 3 is a partial cross-sectional view showing the rice cooker according to the first embodiment of the present invention, including the antimagnetic loop wire attachment member 130. Fig. 4 is a perspective view of main parts showing the rice cooker according to Example 1 of the present invention.

The six antimagnetic loop wires 107 are held by three antimagnetic loop wire attachment members 130 arranged at an angle of approximately 120 degrees to each other, and are respectively fixed outside and below the heating coil 113 . On the antimagnetic loop wire mounting member 130 , there are provided antimagnetic loop wire holes 131 for passing through the antimagnetic loop wires 107 one by one. The antimagnetic loop wire installation member 130 is fastened on the flange 120 of the protection frame 103 by screws 121 . The antimagnetic loop 107 passes between the control substrate 109 and the ferrite 106 .

Six grooves may also be provided on the antimagnetic loop wire mounting member 130 , and each antimagnetic loop wire 107 is sandwiched into the grooves for holding.

The antimagnetic loop wire 107 is a conductive wire. In Example 1, the Hyunflon wire (registered trademark) in which the copper wire 107a is covered with the heat-resistant coating layer 107b was used. The temperature of the inner pot 102 of the electric rice cooker exceeds 100° C. when cooking rice, so the loop wire with heat-resistant coating is used as the antimagnetic loop wire 107 . A current generated by the magnetic flux leaking outward from the outer coil 104 flows through the antimagnetic loop wire 107 . The magnetic flux generated by this current cancels the magnetic flux leaking outward from the outer coil 104 . The anti-magnetic loop wire 107 reduces the magnetic flux leaked from the outer coil 104 to the outside, and suppresses the temperature rise of the body 101 or objects located outside the body 101 .

One antimagnetic loop wire 107 is disposed near the outermost peripheral portion of the outer coil 104 at a position outside and higher than the outermost peripheral portion. Further, another antimagnetic loop wire 107 may be disposed in the vicinity of the innermost peripheral portion of the outer coil 104 at a position further inside and lower than the innermost peripheral portion.

The bottom assembly method of the electric rice cooker of Embodiment 1 of the present invention is as follows. The protective frame 103 is molded by embedding the heating coil 113 exposed to the outside. Then ferrite 106 is provided. Install the antimagnetic loop wire installation member 130 passing through the antimagnetic loop wire 107 on the protective frame 103 with screws 121 . Finally, the temperature sensor 108 , the temperature fuse 114 and the heating coil 113 are connected to the control board 109 . By arranging the temperature sensor signal line 115 substantially perpendicular to the antimagnetic loop line 107 , noise in the temperature sensor signal transmitted from the antimagnetic loop line 107 into the temperature sensor signal line 115 can be reduced.

The rice cooker of Example 1 operates as follows. The user puts cooking items (rice and water) into the inner pot 102 and places them in the protective frame 103 . After the cover 112 is closed, the operation panel (not shown) connected to the operation board is operated to start the operation of the rice cooker. The control board 109 operates, and a current for generating an alternating magnetic field flows through the heating coil 113 . An alternating magnetic field is generated in the heating coil 113 , and an eddy current flows in the inner pot 102 . The Joule heat caused by the eddy current inductively heats the inner pot 102, whereby the food is heated and cooked. The microcomputer (functioning as a control unit) mounted on the control board 109 stores in advance the cooking mode using the temperature of the inner pot 102 detected by the temperature sensor 108 and the cooking time as parameters. The microcomputer performs ON/OFF control of the switching element to control the power supply to the heating coil 113 according to the cooking mode.

Fig. 5 is a diagram showing a configuration of a disconnection detection unit of the rice cooker according to Example 1 of the present invention. The disconnection detection unit is mounted on the control board 109 . The control substrate 109 has a conversion circuit (including: a rectifier bridge 504, a choke coil 505, a smoothing capacitor 507, a current detection unit 506, a heating coil 513, a resonant capacitor 508, a switching element 510, a frequency detection unit 501, and a control unit 509) and Disconnection display part 502. The control unit 509 also serves as a disconnection detection unit.

The rectifier bridge 504, the choke coil 505 and the smoothing capacitor 507 input the commercial power supply, that is, the AC power supply 503, and output a DC voltage. The choke coil 505 prevents the high frequency output from the inverter from leaking from the power line to the outside. The control unit 509 performs ON/OFF control of the switching element 510 . The heating coil 513 and the resonance capacitor 508 form a resonance circuit. When the switching element 510 is driven, a current at a resonance frequency flows through the heating coil 513 and the resonance capacitor 508 .

The current detection unit 506 (current sensor) detects the current flowing in the heating coil 513 . The frequency detection unit 501 detects the frequency of the current flowing in the heating coil 513 . If only one of the antimagnetic loop wires 507 is disconnected, the load of the resonant circuit composed of the heating coil 513 and the resonant capacitor 508 changes, and the resonant frequency also changes. After the control unit 509 detects that the resonant frequency has changed by a predetermined amount (for example, when the inverter circuit is turned ON without putting the inner pot 102 in, or when the antimagnetic loop wire 507 is disconnected, the amount of displacement of the resonant frequency is greatly different, The control unit 509 can identify the cause of the failure), and judges that the antimagnetic loop line 507 is broken. The control unit 509 stops the energization of the heating coil 113 and blinks an LED (Light Emitting Diode) of the disconnection display unit 502 . When the antimagnetic loop wire 507 is disconnected, the control unit 509 may reduce the output power to the heating coil 113 .

In order to clarify the effects of the present invention, experimental data will be described below. The change of the positional relationship between the outer coil and the antimagnetic loop wire and the change of the antimagnetic effect of the antimagnetic loop wire caused by the change of the number of antimagnetic loop wires were investigated. Fig. 6 is a schematic partial sectional view of a rice cooker used in an experiment on which the present invention is based. The outer coil 604 and the inner coil 605 are attached to the protective frame 603, and the ferrite 606 is arranged on the outer side thereof. Ten antimagnetic loop wire holes 621 to 630 are opened on the antimagnetic loop wire mounting member 640 and arranged outside the ferrite 606 . Similar to Embodiment 1 of the present invention, the antimagnetic loop wire is passed between the control substrate and the outer coil. The outer coil is energized, and the maximum value of the magnetic flux density at a distance of 10 cm from the rice cooker body is detected. Table 1 shows the measurement results. The "magnetic shielding efficiency" is a value defined by the ratio (%) of the reduced magnetic flux density when there is a magnetic shielding loop to the magnetic flux density when there is no magnetic shielding loop. The larger the value of the magnetic shielding efficiency, the smaller the magnetic field leaked to the outside of the outer coil 604 . Experiment number Number of anti-magnetic ring wires The location of the magnetic loop Magnetic flux density (μT) Antimagnetic Efficiency (%) 1 0 (none) - 11.00 - 2 10 621～630 3.31 70 3 5 621, 623, 625, 627, 629 4.94 55 4 8 621, 622, 623, 624, 626, 627, 629, 630 3.34 70 5 6 622, 623, 625, 626, 629, 630 4.73 57 6 6 621, 622, 625, 626, 629, 639 4.76 57 7 6 621, 622, 623, 625, 626, 629 4.60 58

In the case of no anti-magnetic loop wire (Experiment No. 1), the magnetic flux density is 11.00μT. When 10 antimagnetic loop wires were arranged around the outer circumference of the outer coil 604 from the upper part of the outer coil upper end 604a to the lower part of the outer coil lower end 604b (Experiment No. 2), the magnetic flux density was reduced by 70% to 3.31 μT. Also, in the case where five antimagnetic loop wires were arranged at equal intervals in the same area (Experiment No. 3), the antimagnetic effect was obtained, but the effect was slightly inferior to that of Experiment No. 2. It can be seen that the antimagnetic loop has an effective antimagnetic effect, and the smaller the interval of the antimagnetic loop, the greater the effect.

In Experiment No. 4, among the 10 antimagnetic loop wires used in Experiment No. 1, the antimagnetic loop wires passing through the antimagnetic loop wire hole 625 and the antimagnetic loop wire hole 628 were removed. As a result, the antimagnetic effect of the same degree as in Experiment 1 was obtained. That is, the closer the antimagnetic ring line is to the upper end 604a of the outer coil and the lower end 604b of the outer coil, the better the antimagnetic effect will be.

In Experiment Nos. 5-7, pass the antimagnetic loop wire through the antimagnetic loop wire hole 625 and the antimagnetic loop wire hole 626, and then pass 4 antimagnetic loop wires through the antimagnetic loop wire holes near the upper end 604a of the outer coil and the lower end 604b of the outer coil. The difference in antimagnetic effect produced by different configurations was investigated. The antimagnetic efficiency in each experiment was 57-58%, and no valuable difference was found. In this way, it is known that by arranging the antimagnetic loop wire near the upper end 604a (outermost peripheral part) of the outer coil at a position outside and higher than the outermost peripheral part and at a position near the lower end 604b (innermost peripheral part) of the outer coil than the innermost peripheral part The inner and lower position can get a good anti-magnetic effect.

Although the data is not shown, it is known that the larger the cross-sectional area of the antimagnetic ring, the better the antimagnetic effect.

In the electric rice cooker of Example 1 of the present invention, the magnetic field leaked from the outer coil is shielded by the linear magnetic shielding loop wire. Thereby, the magnetic field (magnetic flux) leaked to the exterior of a rice cooker is effectively reduced, and a small, lightweight, and cheap rice cooker is realizable. The invention realizes the electric rice cooker which is easy to carry and has good installability.

In Embodiment 1, antimagnetic loop wires are provided above and below the radiator 110 (see FIG. 1 ), but all the antimagnetic loop wires may be wound on the upper side or the lower side of the radiator 110 .

The circuit configuration of the disconnection detection unit is not limited to the configuration shown in FIG. 4 .

The larger the cross-sectional area of the antimagnetic ring, the better the antimagnetic effect. The cross-sectional area of the antimagnetic ring wire is preferably 3.5 square millimeters. The anti-magnetic loop wire is to be provided at a position outside and higher than the outermost peripheral part near the outermost peripheral part of the heating coil or at a position inner and lower than the innermost peripheral part near the innermost peripheral part of the heating coil The cross-sectional area is preferably made larger than the cross-sectional area of other antimagnetic loops. The diameters of the antimagnetic loops arranged at these positions are larger than those of the antimagnetic loops arranged at other positions. Also, a plurality of antimagnetic loop wires are arranged at these positions, and one antimagnetic loop wire (the antimagnetic loop wires have the same diameter) is arranged at other positions.

In order to prevent the magnetic field generated by the inner coil 105, an antimagnetic loop line can also be provided under the bottom of the protective frame. In the case of an electric rice cooker with a heating plate and a heating coil inside the cover, an antimagnetic loop may also be provided between the cover and the heating plate.

The antimagnetic loop wire can also be arranged on the outer peripheral side of the heating coil installed in a container other than the inner pot 102 . For induction heating of the water container installed in the rice cooker, when using a rice cooker that blows high-temperature water vapor on the surface of the rice during the cooking process, if an antimagnetic ring line is installed on the outer peripheral side of the heating coil installed outside the water container, antimagnetic protection can be obtained. Effect.

Example 2

The rice cooker of Example 2 of this invention is demonstrated using FIG. 7. FIG. Fig. 7 is a schematic back view showing an electric rice cooker according to Example 2 of the present invention. The electric rice cooker of embodiment 2 is only different from the electric rice cooker of embodiment 1 in the configuration position of the antimagnetic loop. Other structures are the same as those in Embodiment 1, so descriptions are omitted.

In Embodiment 2, six antimagnetic loop wires 707 are provided on the outer peripheral side of the outer coil 104 and the outer side of the control substrate 109 . In FIG. 2 , only two antimagnetic loop wires 707 are shown in order to make the figure easier to understand. The assembly method of the electric rice cooker bottom of embodiment 2 is carried out as follows.

The protective frame 103 embeds the heating coil 113 exposed to the outside, and is integrally formed with a frame body capable of housing the control board 109 and the heat sink 110 therein. Next, ferrite 106 is provided. Then install the antimagnetic loop wire installation member 130 with the antimagnetic loop wire 107 on the protective frame 103 with screws 121 . Finally, the temperature sensor 108 , the temperature fuse 114 , and the heating coil 113 are connected to the control board 109 . The temperature sensor signal line 115 and the antimagnetic loop line 107 are arranged approximately perpendicularly.

The measured value of the maximum value of the magnetic flux density at a distance of 10cm from the rice cooker body is 11μT when there is no antimagnetic loop wire. The measured values were 5.5 μT and 4.8 μT when the antimagnetic loop wire was provided between the control board 109 and the outer coil and outside the control board 109 , respectively. That is, by providing the antimagnetic loop wire outside the control board, it is possible to effectively shield the magnetic field generated from the outer coil.

Example 3

The rice cooker of Example 3 of this invention is demonstrated using FIG. 8. FIG. Fig. 8 is a partial cross-sectional view showing a rice cooker according to Example 3 of the present invention. The electric rice cooker of embodiment 3 is only different from the electric rice cooker of embodiment 1 in the configuration position of the antimagnetic loop wire. Other structures are the same as those in Embodiment 1, so descriptions are omitted.

The ferrite 106 is disposed outside the outer coil 106 such that its longitudinal direction is substantially perpendicular to the longitudinal direction of the heating coil winding. Further, four antimagnetic loop wires 807 are provided coaxially with the outer coil 104 outside the ferrite 106 . By arranging the antimagnetic loop wire 807 near and above the upper end of the ferrite 106 or near and below the lower end of the ferrite 106, a better antimagnetic effect can be obtained.

Example 4

The rice cooker of Example 4 of this invention is demonstrated using FIG. 9. FIG. Fig. 9 is a partial cross-sectional view showing a rice cooker according to Example 4 of the present invention. Embodiment 4 is different from Embodiment 1 only in the fixing method of the antimagnetic loop wire. Other aspects are the same as in Example 1. The fixing method of the antimagnetic loop wire in the fourth embodiment will be described below.

A heating coil 113 (outer coil 104 and inner coil 105 ) is buried under the protective frame 903 . A plurality of radial ribs 909 are provided outside the heating coil 113 . Each part of the ferrite 106 and the heating coil 113 is buried on the rib 909 at even intervals. Moreover, six antimagnetic loop holes 908 are provided outside the ferrite 106 of the reinforcing rib 909 . One antimagnetic loop wire 907 is disposed in each antimagnetic loop wire hole 908 . The structure other than the structure of the protective frame 903 , the ferrite 106 and the antimagnetic ring 907 is the same as that of the first embodiment, so the description thereof will be omitted.

Because the antimagnetic loop wire is arranged in the antimagnetic loop wire hole formed integrally with the protective frame and provided on the reinforcing rib, the loop wire installation component is no longer needed. Also, the process of fixing the loop wire installation member to the protective frame is unnecessary.

Moreover, in the state where the antimagnetic loop wire is fixed on the protective frame, by integrally molding the protective frame, the installation man-hour of the antimagnetic loop wire can be almost saved. In addition, the heating coil, ferrite and anti-magnetic ring wires can also be integrally formed with the protective frame.

Moreover, it is also possible to set antimagnetic loop wire holes on the ribs that do not embed ferrite, and arrange antimagnetic loop wires. In order to prevent the magnetic field generated from the inner coil 105, reinforcing ribs can also be arranged under the bottom of the protective frame, and an antimagnetic loop line can be buried.

Example 5

The rice cooker of Example 5 of this invention is demonstrated using FIG. 10. FIG. Fig. 10 is a partial cross-sectional view showing a rice cooker according to Embodiment 5 of the present invention. Embodiment 5 is different from Embodiment 1 only in the fixing method of the antimagnetic loop wire. In other respects, Embodiment 5 is the same as Embodiment 1. The fixing method of the antimagnetic loop wire in the fifth embodiment will be described below.

The heating coil 113 (the outer coil 104 and the inner coil 105 ) is buried under the protective frame 1003 with the outer surface almost exposed. A plurality of radial ribs 1009 are provided outside the heating coil 113 . Each part of the ferrite 106 and the heating coil 113 is buried on the rib 1009 at even intervals. Furthermore, five antimagnetic loop wire installation grooves 1008 are provided outside the ferrite 106 of the rib 1009. The antimagnetic loop wires 1007 are clamped in the antimagnetic loop wire installation grooves 1008 one by one. The structure other than the structure of the protective frame 1003, the ferrite 106, and the antimagnetic loop wire 1007 is the same as that of the first embodiment, so the description thereof will be omitted.

Since the antimagnetic loop wire is embedded in the groove for installing the antimagnetic loop wire formed on the reinforcing rib formed integrally with the protective frame, the man-hours for installing the antimagnetic loop wire can be reduced. In addition, the antimagnetic ring wire can also be bonded to the reinforcing rib with an adhesive.

Furthermore, it is also possible to provide a groove for installing an antimagnetic loop wire on the ribs where ferrite is not embedded, and arrange the antimagnetic loop wire.

Example 6

The rice cooker of Example 6 of this invention is demonstrated using FIG. 11. FIG. Fig. 11 is a perspective view showing a ferrite base and antimagnetic loop wire mounting member of an electric rice cooker according to Embodiment 6 of the present invention. Embodiment 6 is different from Embodiment 1 only in the fixing method of the antimagnetic loop wire. In other respects, Embodiment 6 is the same as Embodiment 1. The fixing method of the antimagnetic loop wire in the sixth embodiment will be described below.

The ferrite platform and anti-magnetic loop installation member 1101 is opposite to the outer coil 104 , and fastened outside the protective frame 102 with screws passing through the screw installation part 1102 . The ferrite is buried in the ferrite table and antimagnetic loop wire mounting member 1101 , and a C-shaped groove having a diameter slightly smaller than that of the antimagnetic loop wire 1107 is engraved coaxially with the heating coil 113 . The antimagnetic ring wire 1107 is embedded in the groove 1103 . The rest of the structure is the same as that of Embodiment 1, and its description is omitted here.

The antimagnetic loop wire is embedded in the groove provided on the ferrite table and the antimagnetic loop wire installation component, so no special antimagnetic loop wire installation component is needed. It can ensure the position accuracy of the anti-magnetic ring wire relative to the ferrite, and provide a highly reliable rice cooker.

Example 7

The electric rice cooker of Example 7 of this invention is demonstrated using FIG. 12. FIG. Fig. 12 is a schematic sectional view showing a rice cooker according to Embodiment 7 of the present invention. Embodiment 7 is different from Embodiment 1 only in the fixing method of the antimagnetic loop wire. In Fig. 12, the inner pot 1203, the protective frame 11201, the outer coil 1204, and the inner coil 1205 correspond to the inner pot 102, the protective frame 103, the outer coil 104, and the inner coil 105 in Embodiment 1 (refer to Fig. 1 ), so they are omitted. illustrate. The electric rice cooker of Embodiment 7 also has a protective frame 21202 .

The protection frame 11201 is housed in the protection frame 21202 . The protective frame 21202 is made of resin, and grooves for arranging the antimagnetic loop wire 1207 to face the outer coil 1204 and the inner coil 1205 are engraved on the inner side thereof. The outer surface of the antimagnetic loop wire 1207 is exposed and embedded in the groove. The protection frame 21202 can also be integrally formed with the antimagnetic loop wire 1207 .

The electric rice cooker of Example 7 has the protective frame 2, so it is not as light as the electric rice cookers of Examples 1-6. However, even in the rice cooker of Example 7, the same antimagnetic effect as that of Example 1 was obtained.

In all the above-mentioned embodiments, a plurality of antimagnetic loop wires are arranged concentrically, but one antimagnetic loop wire may be arranged in a helical shape facing the heating coil. In this case, the connection portion of the antimagnetic loop wire is one, and compared with the case of using a plurality of antimagnetic loop wires, the manufacturing process of the rice cooker can be reduced, and a cheaper rice cooker can be realized.

In the present invention, one or more antimagnetic ring wires are arranged outside and/or below the heating coil for inductively heating the container made of magnetic material, so a good antimagnetic effect can be obtained.

The present invention effectively reduces the magnetic field (magnetic flux) leaked from the rice cooker to the outside, and can achieve an advantageous effect that a small, lightweight and inexpensive rice cooker can be realized. According to the present invention, it is possible to achieve an advantageous effect that the rice cooker is easy to carry and has good installation properties.

The preferred embodiment of the present invention has been described in detail, but the content disclosed in the preferred embodiment can be changed in the small part of the structure, and the combination of various elements can be realized within the scope and purpose of the claimed invention and order changes.

Claims (14)

1. an electric cooker is characterized in that, comprising: body, dismounting are contained in described intrinsic container freely and open and close the lid that covers described body freely,

Described body has: the bearer bar of holding said container, 1 or many electric conductivity loop wires being installed on the described bearer bar and described container is carried out the heater coil of eddy-current heating and is arranged on the outside and/or the below of described heater coil.

2. electric cooker as claimed in claim 1 is characterized in that,

Described heater coil comprises the 1st heater coil that most peripheral partly is arranged on the position higher than interior circumferential portion,

To 1 described loop wire of major general, be arranged near the most peripheral part of described the 1st heater coil, than on described most peripheral part more lateral and the high position or be arranged near the interior circumferential portion of described the 1st heater coil, than on described interior circumferential portion inside and the low position.

3. electric cooker as claimed in claim 2, it is characterized in that, be arranged near the most peripheral part of described the 1st heater coil, than on described most peripheral part more lateral and the high position or be arranged near the interior circumferential portion of described the 1st heater coil, bigger than the summation of the sectional area of the electric conductor that is arranged on other locational described loop wires than the summation of the sectional area of the electric conductor of described interior circumferential portion inside and low locational described loop wire.

4. electric cooker as claimed in claim 1; it is characterized in that; also be equipped with control substrate or operation substrate in the periphery side of described bearer bar, be provided in the outside of described control substrate simultaneously to 1 described loop wire of major general to described heater coil supply high frequency electric power.

5. electric cooker as claimed in claim 1, it is characterized in that, described body has the temperature sensor that the temperature to described container detects in the inboard in the interior week of described heater coil, and is adapted to roughly quadrature of the temperature sensor signal line that will transmit to the control substrate from the output signal of described temperature sensor and described loop wire.

6. electric cooker as claimed in claim 1 is characterized in that,

Also have the ferrite member that the magnetic material of one or more high magnetic permeabilities forms in the outside of described heater coil, this member is arranged to its length direction with respect to the length direction of the coiling of described heater coil quadrature roughly,

Be arranged on the downside of the vicinity, bottom of the upside of vicinity, upper end of described ferrite member or described ferrite member to 1 described loop wire of major general.

7. electric cooker as claimed in claim 1 is characterized in that, also have be fixed in described bearer bar or with the integrated loop wire installation component of described bearer bar, at least 1 described loop wire is clamped in the slot part that forms on the described loop wire installation component.

8. electric cooker as claimed in claim 1 is characterized in that, described bearer bar is one-body molded with 1 described loop wire at least.

9. electric cooker as claimed in claim 6 is characterized in that, also is provided with can hold described ferrite and have slot part and be fixed in ferrite platform on the described bearer bar, and at least 1 described loop wire is clamped in the slot part of described ferrite platform.

10. electric cooker as claimed in claim 1 is characterized in that, also has part or all the 2nd bearer bar that holds described bearer bar, and described the 2nd bearer bar is one-body molded with 1 described loop wire at least.

11. electric cooker as claimed in claim 1 is characterized in that, described loop wire coats by having stable on heating cover layer.

12. electric cooker as claimed in claim 1, it is characterized in that also having the burn out detection portion that the broken string to described loop wire detects, when described burn out detection portion detects described loop wire broken string, stop heater coil or reduce its output, and/or demonstrate the situation of described loop wire broken string.

13. electric cooker as claimed in claim 12 is characterized in that, the variation that described burn out detection portion takes place according to the operating frequency of converter detects the broken string of described loop wire.

14. electric cooker as claimed in claim 1 is characterized in that, also has the spool of rolled power line, described spool is arranged on the outside of described loop wire.

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