WO2014080498A1

WO2014080498A1 - Induction-heating cooker

Info

Publication number: WO2014080498A1
Application number: PCT/JP2012/080361
Authority: WO
Inventors: 雄一郎伊藤; 吉野　勇人; 和善根岸; 健太郎橋元; 智也蜷川
Original assignee: 三菱電機株式会社; 三菱電機ホーム機器株式会社
Priority date: 2012-11-22
Filing date: 2012-11-22
Publication date: 2014-05-30
Also published as: TW201420052A; CN204681615U; TWI522076B

Abstract

To obtain an induction-heating cooker capable of efficiently negating magnetic flux leakage produced by a heating coil, and minimizing power loss caused by the magnetic-flux-leakage suppression means itself, an induction-heating cooker (100) is equipped with: a rice-cooker body (1); a heating coil (2) for generating a high-frequency magnetic field and induction-heating the rice-cooker body (1), and positioned on the outside of the rice-cooker body (1); a drive unit (3) for supplying a high-frequency current to the heating coil (2); and a magnetic-flux-leakage suppression means (8) configured from a conductive body for forming a closed loop by electrically shorting both ends, and positioned on the outside of the heating coil (2) when viewed from the rice-cooker body (1), wherein the conductive body is wound around a plurality of times, and at least a portion of the conductive body in the direction in which the conductive body and the heating coil (2) face one another is positioned in a location overlapping at least part of the heating coil (2).

Description

Induction heating cooker

The present invention relates to an induction heating cooker.

In a conventional induction heating cooker, as a means for preventing leakage magnetic flux from the heating coil from leaking to the outside of the induction heating cooker, a nonmagnetic metal such as plate-like aluminum is used as an electromagnetic shielding material around the heating coil. There is something provided. Such an induction heating cooker generates an induction current in the electromagnetic shielding material by the magnetic flux leaked from the heating coil, and cancels the leakage magnetic flux from the heating coil by the magnetic flux generated by this induction current (for example, Patent Documents). 1).

Japanese Examined Patent Publication No. 58-37676 (first page, Fig. 1)

However, in the conventional induction heating cooker, an induction current is generated in the electromagnetic shielding material provided around the heating coil to cancel the leakage magnetic flux from the heating coil. However, the induction current and the electric resistance of the electromagnetic shielding material As a result, the electromagnetic shielding material generated heat, resulting in power loss. In addition, due to the effect of magnetic flux leaked from the heating coil, an induction current is generated not only in the electromagnetic shielding material but also in other metal parts installed inside the casing of the induction heating cooker. Loss due to heat generation also occurred in the parts. For this reason, not only the power consumption of the induction cooking device increases, but also the temperature inside the casing of the induction heating cooking device may increase. When the temperature inside the casing rises, it is necessary to increase the cooling capacity of the cooling means for cooling the inside of the casing, the power supplied to the cooling means increases, and the noise due to the operation of the cooling means also increases. There was a problem.

The present invention has been made in order to solve the above-described problems. An induction heating cooker capable of efficiently canceling the leakage magnetic flux generated from the heating coil and suppressing the power loss of the leakage magnetic flux suppression means itself. Is to provide.

An induction heating cooker according to the present invention includes a cooking container, a heating coil that is disposed outside the cooking container, generates a high-frequency magnetic field to induction-heat the cooking container, and is driven to supply a high-frequency current to the heating coil. And a leakage magnetic flux suppressing means that is disposed outside the heating coil when viewed from the cooking container and is configured by a conductor that is electrically short-circuited at both ends to form a closed loop. In the opposing direction of the conductor and the heating coil, at least a part of the conductor is disposed at a position overlapping with at least a part of the heating coil.

The induction heating cooker of the present invention is provided with leakage magnetic flux suppressing means that is disposed outside the heating coil when viewed from the cooking container and is made of a conductor that is wound over a plurality of turns and electrically shorted at both ends. And at least one part of the conductor which comprises a leakage magnetic flux suppression means is arrange | positioned in the position which overlaps with at least one part of a heating coil in the opposing direction of a conductor and a heating coil. For this reason, by adjusting the number of turns of the conducting wire constituting the leakage flux suppressing means, the leakage current from the heating coil is effectively canceled while reducing the induced current flowing in the conducting wire and suppressing the power loss generated in the conducting wire. be able to.

It is a schematic block diagram of the induction heating cooking appliance which concerns on Embodiment 1. FIG. It is the schematic sectional side view which showed the positional relationship of the rice cooker of the induction heating cooking appliance which concerns on Embodiment 1, a heating coil, and a leakage magnetic flux suppression means. It is a graph which shows the relationship between the ampere turn of conducting wire, and the leakage magnetic flux which generate | occur | produces from an induction heating cooking appliance. It is a figure explaining the modification of the leakage magnetic flux suppression means of the induction heating cooking appliance which concerns on Embodiment 1. FIG. It is a figure explaining the modification of the leakage magnetic flux suppression means of the induction heating cooking appliance which concerns on Embodiment 1. FIG. It is a schematic block diagram of the induction heating cooking appliance which concerns on Embodiment 2. FIG. It is the top view and side view which showed the positional relationship of the 2nd leakage magnetic flux suppression means of the induction heating cooking appliance which concerns on Embodiment 2, and a cord reel. It is a figure explaining the modification of the 2nd leakage magnetic flux suppression means of the induction heating cooking appliance which concerns on Embodiment 2. FIG. It is a figure explaining the structure of the 2nd leakage magnetic flux suppression means of the induction heating cooking appliance which concerns on Embodiment 3. FIG.

Hereinafter, embodiments of an induction heating cooker according to the present invention will be described with reference to the drawings. In addition, this invention is not limited by the form of drawing shown below.

Embodiment 1 FIG.
1 is a schematic configuration diagram of an induction heating cooker according to Embodiment 1. FIG. The induction heating cooker 100 described in the first embodiment is an induction heating type rice cooker, which is a cooking pot 1 as a cooking container, a heating coil 2, a drive unit 3, a display operation unit 4, and a control unit. 5, a power supply unit 6, a cord reel 7, and leakage magnetic flux suppression means 8. Each member shown in FIG. 1 is accommodated in the housing of induction heating cooker 100.

As shown in FIG. 1, a heating coil 2 for inductively heating the rice cooker 1 is disposed on the outer peripheral side of the bottom surface and the lower side surface of the rice cooker 1. The heating coil 2 is supplied with high-frequency power from the drive unit 3 constituting the inverter circuit, and induction-heats the rice cooker 1. The display operation unit 4 includes an operation unit that receives a rice cooking instruction and a rice cooking condition setting from a user, and a display unit that displays an operation state, a message to the user, and the like. The display operation unit 4 outputs a signal based on the setting from the user to the control unit 5, and the control unit 5 including a microcomputer and a control circuit performs a predetermined control sequence based on the signal from the display operation unit 4. Therefore, the drive unit 3 is driven and controlled. The power supply unit 6 generates a power source for driving the display operation unit 4 and the control unit 5 from a commercial AC power source.

The lower part of the heating coil 2 is provided with a cord reel 7 for storing a power cord for connection with a commercial AC power source. The casing of the cord reel 7 is made of sheet metal (iron or the like). For example, the cord reel 7 is located on the opposite side of the rice cooker 1 with the heating coil 2 in between (the lower side of the heating coil 2 in the example of FIG. 1).

In addition, although not particularly illustrated, the induction heating cooker 100 includes a blower that sends cooling air for cooling the members in the casing of the induction heating cooker 100. This blower is, for example, an axial fan, and is configured to send cooling air to a member whose temperature rises due to operation, such as an electronic component provided in the heating coil 2 or the drive unit 3.

Further, the induction heating cooker 100 is provided with leakage magnetic flux suppression means 8 composed of a conductive wire (winding wire) wound in a coil shape so as to surround the rice cooker 1 and the heating coil 2. Leakage magnetic flux suppression means 8 is disposed outside heating coil 2 as viewed from rice cooker 1 that is the object to be heated, with a gap between heating coil 2. That is, the leakage magnetic flux suppression means 8 is disposed at a position where the heating coil 2 is sandwiched between the rice cooker 1 and the leakage magnetic flux suppression means 8. Moreover, the heating coil 2 and the conducting wire constituting the leakage magnetic flux suppressing means 8 are not in contact with each other, and there is a gap between them. Both ends of the conducting wire constituting the leakage magnetic flux suppressing means 8 are short-circuited to form an electrically closed loop. A linear conductor material such as a copper wire or an aluminum wire can be used as the conducting wire of the leakage magnetic flux suppressing means 8. Alternatively, a plate-shaped conductor material, for example, an aluminum plate wound in a coil shape may be used as the leakage magnetic flux suppressing means 8. In addition, the conducting wire which comprises the leakage magnetic flux suppression means 8 shall be insulated with the coating | cover etc., and shall not conduct | electrically_connect even if the mutually adjacent conducting wire contacts. When insulation treatment is not performed on the conducting wires, a sufficient distance is taken between the conducting wires so as not to contact each other.

FIG. 2 is a schematic cross-sectional side view showing the positional relationship among the rice cooker, heating coil, and leakage magnetic flux suppressing means of the induction heating cooker according to the first embodiment. As shown in FIG. 2, the leakage magnetic flux suppression means 8 is provided at a position facing the rice cooker 1 around the heating coil 2, and as shown by a broken line in the figure, the conductive wire constituting the leakage magnetic flux suppression means 8. Is disposed so as to overlap at least a part of the heating coil 2 in the facing direction. Further, in the first embodiment, the lower end of the conducting wire of the leakage magnetic flux suppressing means 8 is located below the upper end of the heating coil 2 and above the lower end of the heating coil 2, and the heating coil 2 in a side view. And the conducting wire constituting the leakage magnetic flux suppression means 8 overlap in the height direction.

Further, as shown in FIG. 2, a ferrite core 9 is installed near the lower side of the heating coil 2.

Heretofore, the configuration of the induction heating cooker 100 according to the first embodiment has been described. Next, operation | movement of the induction heating cooking appliance 100 which concerns on this Embodiment 1 is demonstrated.

When the user inputs an instruction to start heating such as a rice cooking instruction to the display / operation unit 4, the control unit 5 starts controlling the drive unit 3. The drive unit 3 is configured by an inverter circuit and supplies a high frequency current to the heating coil 2. When a high-frequency current flows through the heating coil 2, an alternating magnetic field is generated from the heating coil 2, whereby a magnetic flux is given to the rice cooker 1 that is an object to be heated. When the magnetic flux is applied, an eddy current is generated in the rice cooker 1, and Joule heat is generated by the eddy current and the electric resistance of the rice cooker 1, and the rice cooker 1 is heated.

When the high-frequency current is supplied to the heating coil 2 in this way, magnetic flux is generated from the heating coil 2 and the rice cooker 1 is heated. However, not all the magnetic flux generated from the heating coil 2 is used for induction heating of the rice cooker 1, and a part of the magnetic flux generated from the heating coil 2 does not contribute to the heating of the rice cooker 1, so-called leakage magnetic flux. And emitted to the surroundings. This leakage magnetic flux interlinks with the leakage magnetic flux suppressing means 8 formed in a coil shape. In other words, the leakage flux suppressing means 8 is arranged so as to interlink with the magnetic flux generated from the heating coil 2. When the leakage magnetic flux is linked to the leakage magnetic flux suppression means 8, an electromotive force is generated in the direction that cancels the leakage magnetic flux, and an induced current flows in the conducting wire constituting the leakage magnetic flux suppression means 8. Thus, since a part of the leakage magnetic flux generated from the heating coil 2 is canceled by the induction current generated in the leakage magnetic flux suppressing means 8, the magnetic flux leaking outside the casing of the induction heating cooker 100 is reduced.

The leakage flux canceling effect of the leakage flux suppressing means 8 is more effective as the magnetic field generated from the leakage flux suppressing means 8 is stronger. The magnetic field generated in the leakage flux suppressing means 8 is proportional to the current flowing in the conducting wire constituting the leakage flux suppressing means 8 and the number of turns of the conducting wire. Therefore, the greater the current flowing through the conductor, or the greater the number of turns of the conductor, the higher the effect of suppressing leakage flux. FIG. 3 is a graph showing the relationship between the ampere turn of the conductor (the product of the current flowing through the conductor and the number of turns) and the leakage magnetic flux generated from the induction heating cooker based on the experimental results. As shown in FIG. 3, it can be seen that the greater the ampere turn, the higher the effect of suppressing leakage flux.

Here, the power loss P generated in the leakage magnetic flux suppressing means 8 can be obtained from P = I ² · R from the current I flowing through the conducting wire and the electrical resistance R of the conducting wire. Thus, since the power loss is proportional to the square of the current, it is effective to reduce the current in order to reduce the power loss of the leakage magnetic flux suppressing means 8. And, by reducing the current, the ampere turn is maintained by increasing the number of windings of the conducting wire, and the effect of suppressing the leakage magnetic flux is maintained.

Incidentally, conventionally, as a leakage magnetic flux suppressing means, there is one in which a nonmagnetic metal such as plate-like aluminum is formed in a ring shape and arranged around the heating coil, but the number of turns is equivalent to one turn. Therefore, in order to obtain the leakage magnetic flux suppressing effect, a large current must be passed through the aluminum plate, leading to a large loss.
In this Embodiment 1, since what wound the conducting wire several times is arrange | positioned around the heating coil 2 as the leakage magnetic flux suppression means 8, even if it reduces the electric current which flows through a conducting wire, by ensuring the winding number of conducting wire The power loss generated in the leakage flux suppressing means 8 can be reduced without reducing the leakage flux suppressing effect. Therefore, the power consumption of the induction heating cooker 100 can be reduced and the heating efficiency can be improved.

Note that the current flowing through the conducting wire depends on the resistance value of the conducting wire. If the resistance value of the conducting wire is large, the induced current flowing through the conducting wire decreases. If the resistance value of the conducting wire is small, the induced current flowing through the conducting wire increases. The resistance value of the conducting wire is proportional to the length of the conducting wire and inversely proportional to the cross-sectional area of the conducting wire. Therefore, if the number of turns of the conducting wire is increased, the resistance value increases, and the induced current flowing in the conducting wire tends to decrease. For this reason, in order to appropriately set the ampere turn of the leakage magnetic flux suppressing means 8, the number of turns of the conducting wire and the cross-sectional area (wire diameter) are set to appropriate values, thereby adjusting the induced current flowing through the conducting wire.

As shown in FIG. 2, the conducting wire constituting the leakage flux suppressing means 8 is provided on the outer peripheral portion of the heating coil 2, and at least one part of the conducting wire constituting the leakage flux suppressing means 8 and at least one of the heating coils 2. Are disposed so as to overlap each other in the opposing direction of the conducting wire and the heating coil 2. As described above, the heating coil 2 and at least a part of the conducting wire constituting the leakage flux suppressing means 8 overlap each other in the opposing direction, so that the distance between the heating coil 2 and the conducting wire constituting the leakage flux suppressing means 8 is shortened. The leakage magnetic flux generated in the heating coil 2 is efficiently linked to the leakage magnetic flux suppressing means 8. Thereby, the leakage magnetic flux suppression effect can be heightened.

FIG. 4 is a diagram for explaining a modification of the leakage magnetic flux suppression means of the induction heating cooker according to the first embodiment, and schematically shows the positional relationship among the rice cooker 1, the heating coil 2, and the leakage magnetic flux suppression means 8. It is a sectional side view. In the example shown in FIG. 4, the number of turns of the conducting wire of the leakage magnetic flux suppressing means 8 is increased as compared with that shown in FIG. As shown in FIG. 4, when the number of turns of the conducting wire of the leakage flux suppressing means 8 is increased, the conducting wire is wound in the radial direction so as to suppress the size of the entire leakage flux suppressing means 8 in the height direction. Also good. Thus, by winding a conducting wire over a plurality of layers, the height of the leakage magnetic flux suppressing means 8 can be reduced, and the number of turns can be increased, and the induction heating cooker 100 is limited in the casing. Leakage magnetic flux suppression means 8 set to a necessary ampere turn in the space can be arranged. In FIG. 4, the conductor wire is wound around two layers, but the conductor wire may be wound around three or more layers, for example.

FIG. 5 is a diagram for explaining a modification of the leakage magnetic flux suppressing means of the induction heating cooker according to the first embodiment, and is a schematic side sectional view showing the positional relationship among the rice cooker, the heating coil, and the leakage magnetic flux suppressing means. is there. In the example shown in FIG. 5, the conducting wire constituting the leakage flux suppressing means 8 is arranged along the shape of the outer surface of the heating coil 2 (the surface facing the leakage flux suppressing means 8 of the heating coil 2). Since the heating coil 2 is disposed along the rounded outer wall of the rice cooker 1 on the outer side of the rounded outer wall that connects the side surface and the bottom surface of the rice cooking pot 1, it constitutes the leakage magnetic flux suppressing means 8. By arranging the conducting wire to be arranged along the outer surface shape of the heating coil 2, the conducting wire constituting the leakage flux suppressing means 8 is arranged along the rounded outer wall near the bottom of the rice cooker 1.

Thus, the distance between the conductive wire and the heating coil 2 is determined by arranging the conductive wire constituting the leakage magnetic flux suppression means 8 along the outer shape (outer surface shape) of the heating coil 2 facing the leakage magnetic flux suppression means 8. Can be kept even without partial separation. For this reason, the fall of the leakage magnetic flux suppression effect by the distance of the conducting wire of the leakage magnetic flux suppression means 8 and the heating coil 2 leaving partially can be prevented. In addition, also when increasing the winding number of the conducting wire of the leakage magnetic flux suppressing means 8 as illustrated in FIG. 4, the conducting wire can be wound over a plurality of layers along the outer surface shape of the heating coil 2 according to the example of FIG. 5. .

As described above, in Embodiment 1, the leakage flux suppressing means 8 is configured by winding a conducting wire around the outer periphery of the heating coil 2 over a plurality of circumferences and electrically shorting both ends of the conducting wire. For this reason, even if the induced current flowing in the conducting wire is reduced, it is possible to maintain an ampere turn by winding the conducting wire a plurality of times. Can be reduced. Thus, since the power loss which generate | occur | produces in the leakage magnetic flux suppression means 8 can be reduced, the power consumption of the induction heating cooking appliance 100 can be reduced, and heating efficiency can be improved. Moreover, since the electric power loss which generate | occur | produces in the leakage magnetic flux suppression means 8 can be reduced, the temperature rise inside the housing | casing of the induction heating cooking appliance 100 is also suppressed, and the capability increase of the cooling means for cooling the inside of a housing | casing can be suppressed. For this reason, the power consumption required for the operation of the cooling means and the noise accompanying the operation of the cooling means can be reduced.

Moreover, in this Embodiment 1, since at least one part of the conducting wire of the leakage magnetic flux suppression means 8 is arrange | positioned so that it may overlap with at least one part of the heating coil 2 in the opposing direction with the heating coil 2, the heating coil 2 is used. The leakage flux suppression effect which suppresses that the leakage magnetic flux which generate | occur | produced from the leakage magnetic flux suppression means 8 efficiently links | links, and magnetic flux leaks out of the housing | casing of the induction heating cooking appliance 100 can be heightened.

In the first embodiment, the example in which the conducting wire constituting the leakage magnetic flux suppressing means 8 is wound in a circular shape (annular) around the outer periphery of the heating coil 2 has been shown. However, the shape in which the conducting wire is wound is limited to a circle. For example, the conducting wire may be wound in a square shape in accordance with the outer shape of the induction heating cooker 100.

Embodiment 2. FIG.
In the first embodiment described above, the leakage magnetic flux suppressing means 8 configured by winding the conducting wire around the outer periphery of the heating coil 2 a plurality of times and electrically short-circuiting both ends of the conducting wire is provided from the induction heating cooker 100 to the outside. A method for efficiently reducing the magnetic flux leaking to the head is shown. In the second embodiment, in order to efficiently suppress induction heating of the metal parts arranged inside the induction heating cooker 100 by the leakage magnetic flux from the heating coil 2, the leakage magnetic flux suppression means 8 is Another example in which leakage magnetic flux suppression means (leakage magnetic flux suppression means 10 of the second embodiment) is provided will be described. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and differences from the first embodiment will be mainly described.

FIG. 6 is a schematic configuration diagram of the induction heating cooker according to the second embodiment. The difference from FIG. 1 shown in the first embodiment is that a second leakage magnetic flux suppressing means 10 is provided in a layer between the heating coil 2 and the cord reel 7. The second leakage magnetic flux suppressing means 10 is a coil formed by winding a conducting wire over a plurality of circumferences in a disk shape, and both ends of this conducting wire are short-circuited to form an electrically closed loop. The second leakage magnetic flux suppressing means 10 is located below the heating coil 2 and above the cord reel 7. That is, the second leakage magnetic flux suppressing means 10 is disposed in front of the cord reel 7 when viewed from the heating coil 2.

FIG. 7 is a plan view and a side view showing the positional relationship between the second leakage magnetic flux suppressing means and the cord reel of the induction heating cooker according to the second embodiment. The upper diagram in FIG. 7 is a plan view, and the lower diagram is a side view. As shown in FIG. 7, the second leakage magnetic flux suppressing means 10 is provided on the upper side of the cord reel 7 and is disposed so as to cover the entire casing of the cord reel 7 or a part of the casing. That is, at least a part of the second leakage magnetic flux suppressing means 10 is arranged so as to overlap with at least a part of the cord reel 7 in the direction facing the cord reel 7. The upper surface of the cord reel 7 and the second leakage magnetic flux suppressing means 10 are not in contact with each other, and a gap is provided between them. For example, a copper wire or an aluminum wire insulated with a coating or the like is used as the conductive wire constituting the second leakage magnetic flux suppressing means 10. In addition, when the conductive wires are not insulated, a gap is formed between the conductive wires so that adjacent conductive wires do not contact each other.

The configuration of induction heating cooker 100A according to Embodiment 2 has been described above. Next, the operation of the induction heating cooker 100A will be described. In addition, since the heating operation of induction heating cooker 100A and the effect of leakage magnetic flux suppression means 8 in the second embodiment are the same as those in the first embodiment, here, the operation and action related to second leakage magnetic flux suppression means 10 are described. The explanation will be focused on.

When a user inputs an instruction for starting rice cooking such as a rice cooking instruction to the display operation unit 4, a high frequency current is supplied to the heating coil 2, and the rice cooking pot 1 is heated. At this time, a part of the leakage magnetic flux that does not contribute to the heating of the rice cooker 1 is linked to the second leakage magnetic flux suppressing means 10. Then, an electromotive force is generated in the second leakage flux suppressing means 10 in a direction that cancels the change in the leakage flux, and an induced current flows. As described above, since a part of the leakage magnetic flux generated from the heating coil 2 is canceled out by the induced current generated in the second leakage magnetic flux suppressing means 10, the induction current that has been conventionally generated in the casing of the cord reel 7 can be reduced. The temperature rise of the cord reel 7 can be suppressed.

∙ Low cost iron material may be used for the housing of the cord reel 7 due to the demand for cost reduction. However, since iron is a magnetic material, it is easy to pass magnetic flux and to be easily induction heated. If the cord reel 7 is unavoidably disposed in the vicinity of the heating coil 2 in the limited space of the casing of the induction heating cooker 100A, the casing itself of the cord reel 7 is induction-heated and wasteful power loss occurs. This has led to a reduction in the heating efficiency of the conventional induction heating cooker. However, in the second embodiment, since the second leakage magnetic flux suppressing means 10A is provided, the induced current flowing in the cord reel 7 casing can be reduced, so that the cord reel 7 casing is made of a magnetic flux such as iron. Even when a material that is easy to pass through is used, power loss occurring in the cord reel 7 can be suppressed.

As described in the first embodiment, the effect of canceling the leakage magnetic flux is higher as the magnetic field generated from the second leakage magnetic flux suppressing means 10 is stronger, that is, as the ampere turn of the conducting wire is larger. More specifically, the greater the current flowing through the conducting wire constituting the second leakage magnetic flux suppressing means 10, or the greater the number of turns of the conducting wire, the higher the leakage flux suppressing effect.
Similarly to the description of the leakage flux suppressing means 8 in the first embodiment, the power loss P generated in the second leakage flux suppressing means 10 is the square of the current flowing through the second leakage flux suppressing means 10. Since it is proportional, it is effective to reduce the current flowing through the conducting wire in order to reduce the loss of the second leakage magnetic flux suppressing means 10. And, by reducing the current, the number of windings of the conducting wire is increased, so that an ampere turn can be obtained and the effect of suppressing the leakage magnetic flux can be maintained.

Therefore, in the second embodiment, the second leakage magnetic flux suppressing means 10 is configured by winding a conducting wire in a circular shape a plurality of times. Thus, the conductor wire is wound a plurality of times so that an ampere turn can be ensured even if the current flowing through the conductor wire is small, and the temperature rise of the housing of the cord reel 7 is suppressed while suppressing the heat generation of the second leakage magnetic flux suppressing means 10 itself. Can be suppressed. Therefore, the power consumption of the induction heating cooker 100A can be reduced, and the heating efficiency can be improved.

In addition, since the induced current flowing through the second leakage magnetic flux suppression means 10 depends on the resistance value of the conducting wire, as described in the first embodiment, by adjusting the winding number and cross-sectional area (wire diameter) of the conducting wire, The induced current flowing in the conducting wire of the second leakage magnetic flux suppressing means 10 is adjusted.

FIG. 8 is a diagram for explaining a modification of the second leakage magnetic flux suppression means of the induction heating cooker according to the second embodiment, in which the rice cooker 1, the heating coil 2, the leakage magnetic flux suppression means 8, and the second leakage magnetic flux. FIG. 4 is a schematic side sectional view showing the positional relationship of the suppressing means 10. As shown in FIG. 8, according to the number of turns of the conducting wire of the second leakage magnetic flux suppressing means 10, the conducting wire may be overlapped in the height direction and wound over a plurality of layers. By doing in this way, even when there is little space of a plane direction, the number of windings of a conducting wire can be earned efficiently and a necessary ampere turn can be secured. In FIG. 8, the conducting wire is wound around two layers, but the conducting wire may be provided in a plurality of layers, for example, three or more layers.

Further, as shown by a broken line in FIG. 8, the second leakage magnetic flux suppressing means 10 and the heating coil 2 are arranged at positions where at least a part of them overlaps in the facing direction in the side view. That is, in the example of FIG. 8, when viewed from above, at least a part of the heating coil 2 and at least a part of the second leakage magnetic flux suppressing means 10 overlap. For this reason, the distance of the conducting wire which comprises the heating coil 2 and the 2nd leakage magnetic flux suppression means 10 can be set as short as possible, and the leakage magnetic flux which generate | occur | produced in the heating coil 2 is linked with the 2nd leakage magnetic flux suppression means 10 efficiently. To do. Therefore, the leakage magnetic flux suppression effect which suppresses the leakage magnetic flux from the heating coil 2 leaking outside the induction heating cooking appliance 100A can be heightened.

As described above, in the second embodiment, the second leakage magnetic flux suppressing means 10 configured by winding the conductive wire a plurality of times to form a disk shape and electrically short-circuiting both ends of the conductive wire is used as the heating coil 2 and the cord. A layer between the reels 7 was prepared. For this reason, a part of the leakage magnetic flux generated from the heating coil 2 can be canceled by the second leakage magnetic flux suppressing means 10, and the induction current that has conventionally occurred in the casing of the cord reel 7 can be reduced. Thereby, the temperature rise of the housing of the cord reel 7 can be prevented. Moreover, since the number of windings of the conducting wire of the second leakage flux suppressing means 10 is secured and the induced current flowing through the conducting wire is caused to occur, the heat generation of the second leakage flux suppressing means 10 is suppressed. The electric power loss which generate | occur | produces is suppressed, the power consumption of the induction heating cooking appliance 100 can be reduced, and a heating efficiency can be improved. Moreover, since the temperature rise of the 2nd leakage magnetic flux suppression means 10 and the cord reel 7 can be suppressed, the temperature rise inside the housing | casing of the induction heating cooking appliance 100A is also suppressed, and the inside of the housing | casing of the induction heating cooking appliance 100A is cooled. The cooling capacity of the cooling means can be reduced, and the power consumption of the cooling means and the noise accompanying the operation of the cooling means can be reduced.

Embodiment 3 FIG.
In the above-described second embodiment, the example in which the second leakage magnetic flux suppressing means 10 is configured by a conducting wire wound in a disk shape is shown. In the third embodiment, another configuration example of the second leakage magnetic flux suppressing means 10 will be described. In the third embodiment, the difference from the second embodiment will be mainly described.

FIG. 9 is a diagram illustrating a configuration of second leakage magnetic flux suppressing means of the induction heating cooker according to the third embodiment. The upper view of FIG. 9 is a plan view, and the lower view is a side view.
As shown in FIG. 9, the second leakage magnetic flux suppressing means 10 </ b> A is obtained by forming a coil as the pattern wiring 11 on the printed board 13. The printed circuit board 13 is a printed circuit board of a base material such as a glass epoxy board, for example, and can be wired on both sides. The pattern wiring 11 is formed on the printed circuit board 13 with a copper foil or the like, and the second leakage flux suppressing means 10A Is configured. The pattern wiring 11 constituting the second leakage magnetic flux suppression means 10A has a coil portion formed in a spiral shape. In the example of FIG. 9, for example, the coil portion of the pattern wiring 11 starts from the coil outer end 12 a located near the outer periphery of the printed circuit board 13, and the pattern wiring 11 is formed in a spiral shape to the coil inner end 12 b. , And electrically connected to the back surface of the printed circuit board 13 through the through hole. Although not shown, the pattern wiring 11 is formed in a spiral shape from the inside of the back surface of the printed board 13 to the outside of the back surface of the substrate in the same direction as the winding direction of the front surface. The end of the coil on the back side is electrically connected to the coil outer end 12a on the surface of the substrate through a through hole. That is, the starting point and the ending point of the coil formed by the pattern wiring 11 are electrically connected to form a closed circuit.

The printed circuit board 13 constituting the second leakage magnetic flux suppressing means 10A is arranged in a layer between the heating coil 2 and a metal part (for example, the cord reel 7) constituting a part of the induction heating cooker 100A. That is, these are arranged so that the heating coil 2 and the metal parts such as the cord reel 7 face each other with the second leakage magnetic flux suppressing means 10A interposed therebetween. In the third embodiment, since the second leakage magnetic flux suppressing means 10A is constituted by the printed circuit board 13 and the pattern wiring 11 formed on the printed circuit board 13, the second leakage magnetic flux suppressing means 10A is set to the thickness of the printed circuit board 13. Can be made thin. Therefore, even when the installation space is narrow, such as when placed below the heating coil 2, the second leakage magnetic flux suppressing means 10A can be installed. Thereby, size reduction and thickness reduction of induction heating cooking appliance 100A are realizable.

In the second embodiment, the glass epoxy base material is exemplified as the base material of the printed circuit board 13, but the base material of the printed circuit board 13 is not limited to this, and the pattern constituting the second leakage magnetic flux suppressing means 10A. Depending on the coil diameter, pattern width, and number of turns of the wiring 11, for example, the pattern wiring 11 may be single-sided on a paper phenol substrate, or the multilayer pattern wiring 11 may be provided on a multilayer substrate.

As described above, in the third embodiment, the second leakage magnetic flux suppressing means 10A made of a coil formed by the pattern wiring 11 on the printed board 13 is provided between the heating coil 2 and the cord reel 7 in the facing direction. It was. For this reason, a part of the leakage magnetic flux generated from the heating coil 2 can be canceled by the second leakage magnetic flux suppressing means 10A, and the induction current that has conventionally occurred in the casing of the cord reel 7 can be reduced. Thereby, the temperature rise of the housing of the cord reel 7 can be prevented.
Moreover, in this Embodiment 3, since the 2nd leakage magnetic flux suppression means 10A was comprised by giving the pattern wiring 11 to the printed circuit board 13, the 2nd leakage magnetic flux suppression means 10A can be thinned to the thickness of the printed circuit board 13, The induction heating cooker 100A can be reduced in size and thickness.

In the second and third embodiments, the arrangement example of the second leakage magnetic

flux suppressing means

10 and 10A for suppressing the induced current flowing in the cord reel 7 is shown. However, in the second leakage magnetic

flux suppressing means

10 and 10A, The object to be electromagnetically shielded is not limited to the cord reel 7, and the second leakage magnetic

flux suppressing means

10, 10 </ b> A is similarly applied to other metal parts in the casing of the induction heating cooker 100 </ b> A following the example of the cord reel 7. By arranging, the same effect can be obtained.

In the second and third embodiments, the example in which the second leakage magnetic

flux suppressing means

10 and 10A are arranged between the metal component (code reel 7) provided below the heating coil 2 has been described. The arrangement of the component and the second leakage magnetic

flux suppressing means

10, 10A is not limited to this. For example, in the case of the induction heating cooker 100A in which the metal part is arranged on the side surface of the heating coil 2, the second leakage magnetic flux suppressing means 10 is located on the side of the heating coil 2 and between the heating coil 2 and the metal part. 10A may be provided. In this way, by arranging the second leakage magnetic

flux suppressing means

10 and 10A between the heating coil 2 and the metal part, a part of the leakage magnetic flux generated on the side surface of the heating coil 2 is changed to the second leakage magnetic flux. The suppression means 10, 10 </ b> A can cancel out, the temperature rise of the metal parts is suppressed, and the power loss is reduced.

Moreover, in Embodiment 2, the example which wound the conducting wire which comprises the 2nd leakage magnetic flux suppression means 10 in circular shape (annular) was shown, However, The shape which winds a conducting wire is not limited to circle, For example, conducting wire is made into a square. You may roll it up.
In the third embodiment, the pattern wiring 11 constituting the second leakage magnetic flux suppressing unit 10A is circular. However, the shape of the pattern wiring 11 is not limited to a circle. For example, the pattern wiring 11 is rectangular. It may be formed.

Further,

Embodiments

1, 2, and 3 can be combined with each other, and even in such a case, the effects described in the embodiments can be obtained.
Further, the leakage magnetic flux suppressing means 8 shown in the first embodiment can be omitted, and the second leakage magnetic

flux suppressing means

10, 10A shown in the second and third embodiments can be provided in the induction heating cooker.
In the first to third embodiments, an example in which the present invention is applied to a rice cooker has been shown. However, if the induction heating cooker is provided with a cooking container and a heating coil for induction heating the cooking container, for example, electric The present invention can also be applied to a pot or a water heater.

1 rice cooker, 2 heating coil, 3 drive section, 4 display operation section, 5 control section, 6 power supply section, 7 cord reel, 8 leakage flux suppression means, 9 ferrite core, 10 leakage flux suppression means, 10A leakage flux suppression means 11 pattern wiring, 12a coil outer end, 12b coil inner end, 13 printed circuit board, 100 induction heating cooker, 100A induction heating cooker.

Claims

A cooking container;
A heating coil disposed outside the cooking vessel and generating a high-frequency magnetic field to inductively heat the cooking vessel;
A driving unit for supplying a high-frequency current to the heating coil;
Leakage magnetic flux suppression means that is disposed outside the heating coil as seen from the cooking container, and is configured by a conductor that is electrically short-circuited at both ends to form a closed loop,
The conductor is wound over a plurality of circumferences,
In an induction heating cooker, at least a part of the conductor is disposed at a position overlapping with at least a part of the heating coil in a facing direction of the conductor and the heating coil.
2. The induction heating cooker according to claim 1, wherein at least a part of the conductor constituting the leakage magnetic flux suppressing means is arranged at an equal distance from the heating coil along an outer shape of the heating coil. .
Comprising a metal part arranged on the opposite side of the cooking vessel with the heating coil in between;
The leakage magnetic flux suppression means is disposed in front of the metal component as viewed from the heating coil,
2. The induction heating according to claim 1, wherein at least a part of the conductor constituting the leakage magnetic flux suppressing means is disposed at a position overlapping at least a part of the metal part in a facing direction of the metal part. Cooking device.
The induction heating cooker according to claim 3, wherein the conductor constituting the leakage magnetic flux suppressing means is formed as a pattern wiring on a printed board.
The induction heating cooker according to any one of claims 1 to 4, wherein at least a part of the conductor constituting the leakage magnetic flux suppressing means is wound in a plurality of layers.