JP5202675B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker, and more particularly to a heating cooker provided with means for detecting spillage from a cooking container or the like placed on a top plate.

  In an induction heating cooker, when a cooking container in which an object is to be cooked is heated, the object to be cooked may reach the boiling point and spill out of the cooking container. In such a case, if the heating is continued without stopping or reducing the heating power, the food to be cooked spills from the cooking container one after another and cannot be operated by the operation part or cannot be cleaned by entering the intake / exhaust port. There are things. In addition, there are various inconveniences such as the food to be spilled on the top plate sticking to the top plate due to heat.

  In order to solve such a problem, an electrode is arranged in the vicinity of the heating coil on the lower surface of the top plate in a conventional induction heating cooker equipped with means for detecting spillage from a cooking container or the like, and the electrode and a predetermined potential are arranged. In some cases, the occurrence of spillage is detected from the change in capacitance between them (for example, see Patent Documents 1 and 2).

Japanese Patent Laying-Open No. 2008-159494 (page 7-8, FIG. 1) JP 2010-182659 A (page 8-10, FIGS. 1 and 2)

  In the induction heating cooker of Patent Document 1, since the electrodes are locally arranged in the vicinity of or around the heating coil, if there is spilling in a place where no electrode is arranged, the spilling has approached the periphery of the operation unit. Because it cannot be detected, the operation part will be covered with hot spilled contents, and not only will it not be able to stop the operation, but it will also cause burns if the user tries to stop the operation. There was a fear.

  In addition, as shown in FIG. 8, the induction heating device of Patent Document 2 is arranged on the lower surface of the top plate 10 along the edge of the heating port 11 provided on the upper surface of the top plate 10 corresponding to the heating coil. By arranging the electrode 15, it is possible to detect spillage at an early stage. However, if the sink is tilted or the induction heating device is tilted and incorporated in the sink, the spill does not reach the electrode 15. For this reason, it was impossible to reliably detect spillage.

  In order to solve such a problem, if the electrode is arranged along the edge of the heating coil so as to enclose the heating port, not only the area of the electrode is increased, the cost is increased, but also the static electricity is placed above the electrode. Since the cooking container which becomes a disturbance at the time of electric capacity detection is mounted, there existed a problem that a misdetection was easy to generate | occur | produce.

  The present invention has been made to solve the above-described problem, and can quickly and surely detect spillage from an object to be heated on the top plate and control the high-frequency current supplied to the heating means. The purpose is to provide a safe and reliable induction heating cooker.

The induction heating cooker according to the present invention includes a top plate having a top plate coating on the upper surface, on which an object to be heated is placed, and a heating means disposed below the top plate to heat the object to be heated. A driving circuit that supplies a high-frequency current to the heating unit, an operation control unit that controls the driving circuit, an electrode that is provided on the lower surface of the top plate along a part of the outer periphery of the heating unit, A capacitance detection unit that detects a capacitance between the electrode and a predetermined potential, and based on a measurement result of the capacitance detection unit, the operation control unit causes the operation control unit to prevent spillage from the object to be heated. Configured to detect,
In the top plate coating, the density state of the capacitance region facing the electrode on the upper surface is made different from the peripheral top plate coating.

  According to the present invention, the liquid spilled on the top plate is likely to remain above the electrodes, that is, in the capacitance region. Therefore, even when the top plate is inclined or the amount of spillage is small, Since the occurrence of spillage can be detected in accordance with the change in capacitance by being guided to the capacity region, a safe and reliable induction heating cooker can be obtained.

It is a disassembled perspective view which shows the structure of the induction heating cooking appliance in Embodiment 1 of this invention. It is a block diagram of the principal part of FIG. It is a cross-sectional explanatory drawing of the principal part of FIG. It is a top view of the induction heating cooking appliance which concerns on Embodiment 1. FIG. It is a top view of the principal part of the other example of FIG. It is a top view of the principal part of the induction heating cooking appliance which concerns on Embodiment 2 of this invention. It is a top view of the principal part of the induction heating cooking appliance which concerns on Embodiment 3 of this invention. It is a top view of the conventional induction heating cooking appliance.

[Embodiment 1]
In FIGS. 1-3 which show the structure of the induction heating cooking appliance which concerns on Embodiment 1 of this invention, 1 is an induction heating cooking appliance, 2 is the box-shaped main-body part by which upper part was opened, 10 is the main-body part 2. This is a top plate on which the cooking container 30 (hereinafter, referred to as the object to be heated) is placed so as to close the upper opening of the container and in which the object to be cooked is placed.

  In the main body 2, heating coils 3 a, 3 b, 3 c (hereinafter simply referred to as 3) which are heating means for generating an induction magnetic field for heating an object to be heated, and an alternating voltage to a high frequency voltage A drive circuit 4 for converting and supplying a high-frequency current to the heating coil 3 is provided. Reference numeral 5 denotes a drawer-type grill.

  The top plate 10 has ring-shaped heating ports 11a, 11b, and 11c (hereinafter simply referred to as 11) indicating positions where the object 30 is placed at positions corresponding to the heating coils 3a to 3c on the upper surface. Are provided by printing or the like, and on the front side of the top plate 10, operation units 12a, 12b, and 12c (hereinafter simply referred to as 12) for setting the input power to the heating coils 3a to 3c and the like. May be provided). Reference numeral 13 denotes a display unit. Further, on the back side of the top plate 10, an intake port 14a for taking in cooling air for cooling the heating coil 3 and the drive circuit 4 in the main body 2 and an exhaust port 14b for discharging the cooled air. Is provided.

FIG. 1 shows a case where the heating coil 3 is wound in a triple ring shape to provide a space between the rings. However, the present invention is not limited to this. For example, a single ring shape in which no space is provided between the rings. Alternatively, a single heating coil 3 may be configured by arranging a plurality of non-concentric rings, and the shape thereof is not limited to the ring shape, and may be an elliptical shape or a rectangular shape. Furthermore, although the case where the three heating coils 3 were provided in the main-body part 2 was shown, 1 piece or 4 or more may be sufficient and a resistance heater etc. may be provided in one part.
Moreover, although the case where the heating port 11 was enclosed by the ring was shown, another shape may be sufficient.

Near the heating ports 11 a to 11 c on the lower surface of the top plate 10, substantially arc-shaped electrodes 15 are provided along the heating ports 11 a to 11 c, and thus along a part of the outer periphery of the heating coil 3. It has been. An operation unit case 6 having a control operation unit 7 connected to each operation unit 12 corresponding to each operation unit 12a to 12c is provided on the upper front side of the main body unit 2, and the control operation unit 7 or in the vicinity thereof, a capacitance detection unit 8 is provided for detecting a change in capacitance generated in the electrode 15 when a spill from the heated object 30 flows onto the top plate 10. .
As shown in FIG. 2, the capacitance detection unit 8 detects a change in capacitance generated in the electrode 15 and sends the result to the operation control unit 7. The operation control unit 7 drives based on the change. The circuit 4 is controlled and the heating coil 3 is driven.

The electrode 15 is formed on the lower surface of the top plate 10 along the front side of each of the heating ports 11a to 11c, for example, by applying or bonding a conductor, and one end thereof is the capacitance detection unit 8. The other end of the conductive member 9 connected to is in contact with the electrode 15 and is electrically connected when the top plate 10 is mounted on the main body 2.
Thus, the electrode 15 forms a conductor and a capacitor on the top plate 10, and the capacitance is detected by the capacitance detection unit 8 via the conductive member 9. The electrode 15 is provided on the lower surface of the top plate 10, but in each drawing, the electrode 15 is indicated by a solid line on the upper surface of the top plate 10 for easy understanding.

In the above description, the case where the capacitance between one electrode 15 provided on the front side of the heating port 11 and the conductor on the top plate 10 is measured is shown. Alternatively, two electrodes 15 may be provided, and the capacitance between the two electrodes 15 may be measured.
By comprising in this way, it can make it difficult to receive the influence of noise, such as a magnetic field produced at the time of the induction heating of the to-be-heated material 30. FIG.

Further, as shown in FIG. 4, the top plate 10 is placed on the top surface of the top plate 10 to prevent the heated object 30 from coming into close contact with the top plate 10 or from falling due to the falling of the heated object 30. In order to prevent damage, a top plate coating 20 is provided to form dots and stripe-like grooves.
In the present embodiment, the density of the top coating 20 at a position corresponding to the electrode 15 provided on the lower surface of the top plate 10 and its surroundings (hereinafter, this portion is referred to as the capacitance region 16) is rougher than the surroundings. (Sparsely) or the top plate coating 20 in this portion is omitted. FIG. 4 shows a case where the top plate coating 20 in the capacitance region 16 is omitted.

FIG. 5 shows another example of the top plate coating 20 on the top plate 10. In the case of FIG. 5A, the liquid spilled on the top plate 10 in the front-rear direction of the top plate 10 is a capacitance region. A top plate coating 20 having a plurality of stripe-like grooves inclined toward the direction 16 is provided.
Further, in the case of FIG. 5B, a top plate coating 20 having a plurality of stripe-like grooves that cross the left and right on the top plate 10 is provided. 16 top plate coating 20 is omitted.

Next, the operation of the present embodiment configured as described above will be described.
When the relative dielectric constant (mainly air) between the electrode 15 of area A and the conductor on the top plate 10 is K, the distance is d, and the vacuum dielectric constant is K0, the capacitance C is C = K It is calculated | required by * K0 * A / d.
In a state where there is no spillage, air having a relative dielectric constant of 1 exists mainly above the electrode 15 via the top plate 10. When spilling occurs, moisture having a relative dielectric constant of 80 flows onto the top plate 10 (capacitance region 16) facing the electrode 15, and the capacitance C increases rapidly.
Thus, the presence or absence of spillage can be determined by detecting the change in the capacitance C by the capacitance detection unit 8.

  In the induction heating cooker provided with such a spill detector, when the user turns on the power switch and operates the operation unit 12, the drive circuit 4 is driven by the operation control unit 7, and a high-frequency current is generated in the heating coil 3. The heated object 30 is heated by the high-frequency magnetic field that is supplied and generated in the heating coil 3.

  While the object to be heated 30 is being heated, the capacitance detector 8 detects a change in the capacitance C of the electrode 15 at regular time intervals, and determines whether or not spilling has occurred. When the capacitance C increases rapidly, it is determined that a spill has occurred, and the capacitance detection unit 8 sends the spill information to the operation control unit 7. The operation control unit 7 controls the drive circuit 4 so as to stop or reduce the current supplied to the heating coil 3 based on this information. At this time, the operation control unit 7 may issue an alarm.

  According to the present embodiment, the top plate 10 is provided with a rough top plate coating on the capacitance region 16 on the top surface of the top plate 10, or the top plate coating of the capacitance region 16 is omitted. The liquid easily flows and exists in the capacitance region 16. For this reason, even when the level of the top plate 10 is not maintained at the time of assembling or when the main body 2 is inclined when being assembled into the kitchen, it is possible to reliably detect the spillage.

  Further, the liquid spilled on the top plate 10 is applied with a rough top plate coating from the peripheral top plate coating 20 or easily flows into the capacitance region 16 where the top plate coating is omitted, so that the detection accuracy of the spillage is improved. Can be improved. In particular, when the top plate coating of the capacitance region 16 is omitted, the effect is great.

Further, in the present embodiment, as shown in FIGS. 4 and 5A, the stripe-shaped groove is formed by the top plate coating 20 so as to face the capacitance region 16. This makes it easier for the liquid spilled over to the capacitance region 16 to improve the detection accuracy.
Further, as shown in FIG. 5B, if a stripe-shaped groove is formed by the top plate coating 20 so as to cross the left and right directions of the top plate 10, the liquid spilled on the top plate 10 will flow along the groove. Flow to the operation unit 12 provided on the front side of the top plate 10 and the cooling air intake port 14a and the exhaust port 14b provided on the rear side. Can be prevented and reliability can be improved.

  Further, according to the present embodiment, the density of the top plate coating of the capacitance region 16 of the top plate 10 corresponding to the position of the electrode 15 is changed with respect to the peripheral top plate coating 20, so When the user looks at the top plate 10, the position and shape of the electrode 15 (capacitance region 16) can be visually recognized. For this reason, it is possible to prevent the heated object 30 from being erroneously placed on the capacitance region 16 and changing the capacitance so that the capacitance detection unit 8 determines that the spill has occurred. Therefore, a highly reliable device for detecting spillage can be obtained.

  Furthermore, according to the present embodiment, even when the area of the electrode 15 is small or the amount of liquid spilled is small, the top plate coating provided in the capacitance region 16 is compared with the peripheral top plate coating 20. Since it is roughened or omitted, the liquid can be reliably guided onto the electrode 15. For this reason, not only can the electrode 15 be reduced in size and cost can be reduced, but also erroneous detection of spillage caused by the object 30 to be heated placed on the capacitance region 16 can be prevented. .

[Embodiment 2]
FIG. 6 is a plan view of a main part of the induction heating cooker according to Embodiment 2 of the present invention. Parts having the same or the same functions as those in the first embodiment are denoted by the same symbols.
In the present embodiment, the position of the top surface of the top plate 10 facing the electrode 15 placed on the bottom surface of the top plate 10 and its periphery, that is, the top plate coating 20a in the capacitance region 16 is applied to the peripheral top plate. It is formed finer (densely) than 20. In the figure, a case where a stripe-like groove is formed in the front-rear direction of the top plate 10 by the top plate coating 20 on the top surface of the top plate 10 is shown.

  According to the present embodiment, the top plate coating 20 a is provided in the capacitance region 16 more densely than the peripheral top plate coating 20, so that the liquid spilled on the top plate 10 is the capacitance region above the electrode 15. When it reaches 16, it does not easily flow out to the portion of the surrounding rough top plate coating 20, and stays at that position.

  Also in the present embodiment, the capacitance detection unit 8 detects a spill from the object to be heated 30, and the operation control unit 7 controls the drive circuit 4 based on this to supply a high frequency current to the heating coil 3. The action of stopping or reducing the same is the same as in the first embodiment.

  According to the present embodiment, substantially the same effect as in the case of the first embodiment can be obtained, but the top plate coating 20a denser than the peripheral top plate coating 20 is further provided in the capacitance region 16. Therefore, the liquid spilled on the top plate 10 tends to stay on the electrode 15 (capacitance region 16), and the occurrence of spilling is reliably detected even when the level of the top plate 10 is not maintained. be able to.

  In particular, when the change in the capacitance of the electrode 15 is measured at regular time intervals, the liquid that has been spilled on the top plate 10 when it has not been measured flows out without remaining in the capacitance region 16. Although the change in capacitance cannot be accurately captured, according to the present embodiment, the spilled liquid stays in the capacitance region 16 even in such a case, so the change in capacitance is always detected. It can be detected reliably.

[Embodiment 3]
FIG. 7 is a plan view of the main part of an induction heating cooker according to Embodiment 3 of the present invention. In addition, the same code | symbol is attached | subjected to the part of the same or same function as Embodiment 1,2.
In the present embodiment, the position of the top surface of the top plate 10 facing the electrode 15 provided on the bottom surface of the top plate 10 and the top plate coating 20a of the surrounding capacitance region 16 are rougher than the peripheral top plate coating 20. Alternatively, the top plate coating 20a of the portion (hereinafter referred to as the outer peripheral region 17) provided along the capacitance region 16 on the near side of the capacitance region 16 is finer than the peripheral top plate coating 20 in the vicinity thereof. (Densely) formed. In the figure, a strip-like top plate coating 20 that traverses in the left-right direction is provided on the top plate 10 (including the capacitance region 16 and the outer peripheral region 17), and further, the capacitance region 16 and the outer periphery are provided. Although the case where the top plate coating 20a is provided in the direction orthogonal to the peripheral top plate coating 20 is shown in the area 17, it is not limited to this.

  Also in the present embodiment, the capacitance detection unit 8 detects a spill from the object to be heated 30, and the operation control unit 7 controls the drive circuit 4 based on this to supply a high frequency current to the heating coil 3. The action of stopping or reducing the same is the same as in the first and second embodiments.

  According to the present embodiment, substantially the same effect as in the first and second embodiments can be obtained, but a dense ceiling is provided on the front side of the capacitance region 16 of the top panel coating 20a that is rougher than the peripheral top panel coating 20. Since the outer peripheral region 17 of the plate coating 20a is further provided, the liquid spilled on the top plate 10 from the object to be heated 30 stays in the capacitance region 16 and is prevented from flowing out to these peripheral regions. As a result, the reliability of detection of spilling can be further increased.

  Further, since the spilled liquid stays in the capacitance region 16 and can be prevented from flowing out and spreading on the top plate 10 from here, it flows on the operation unit 12 or flows into the intake port 14a or the exhaust port 14b. Therefore, an induction heating cooker with high safety and cleanability can be obtained.

  In the above description, the case where the present invention is applied to a built-in type induction heating cooker incorporated in a sink is shown, but the present invention is not limited to this, and the present invention is not limited to a stationary type or tabletop type cooking device. Can also be implemented.

  DESCRIPTION OF SYMBOLS 1 induction heating cooker, 2 main-body part, 3 heating coil, 4 drive circuit, 5 grille, 6 operation part case, 7 operation control part, 8 electrostatic capacitance detection part, 9 conductive member, 10 top plate, 11 heating port, 12 Operation part, 13 Display part, 15 Electrode, 16 Capacitance area | region, 17 Outer periphery area | region, 20 Top-plate coating, 30 To-be-heated object.

Claims (7)

A top plate provided with a top plate coating on the upper surface, on which the object to be heated is placed, a heating means disposed under the top plate for heating the object to be heated, and a high-frequency current supplied to the heating means Drive circuit, an operation control unit for controlling the drive circuit, an electrode provided on the lower surface of the top plate along a part of the outer periphery of the heating means, and a static potential between the electrode and a predetermined potential. A capacitance detection unit that detects a capacitance, and configured to detect spillage from the object to be heated by the operation control unit based on a measurement result of the capacitance detection unit;
An induction heating cooker characterized in that a density state of a capacitance region facing the electrode on the upper surface of the top plate coating is different from that of a peripheral top plate.   The induction heating cooker according to claim 1, wherein the top plate coating of the capacitance region is formed to be rougher than the peripheral top plate coating.   The induction heating cooker according to claim 1, wherein the top plate coating of the capacitance region is formed more densely than the peripheral top plate coating.   The induction heating cooker according to claim 1, wherein the top plate coating of the capacitance region is omitted.   An outer peripheral region is provided along the capacitance region on the near side of the capacitance region, and the top plate coating of the outer peripheral region is formed more densely than the peripheral top plate coating. Or the induction heating cooking appliance of 4.   The strip-like groove inclined so as to face in the front-rear direction of the top plate and in the direction of the capacitance region is formed by a top plate coating provided on an upper surface of the top plate. The induction heating cooker in any one of 1-5.   The induction heating cooker according to any one of claims 1 to 5, wherein a stripe-like groove that crosses the top plate in a left-right direction is formed by painting a top plate provided on an upper surface of the top plate. .