JP6272053B2 - Induction heating cooker - Google Patents

Description

  The present invention relates to an induction heating cooker that induces an eddy current in a pot-shaped container to heat the pot-shaped container.

  In a conventional cooking device, in a rice cooker that is a kind of cooking device, “a rice cooker body, a pan equipped in the rice cooker body, a heating means for heating the pan, and a lid that covers the rice cooker body And a pan temperature detecting means for detecting the temperature of the pan, and a heating control means for controlling the heating means in accordance with a predetermined rice cooking sequence according to the output of the pan temperature detecting means, wherein the pan is dimpled on the bottom inner surface. And a wall portion formed in an annular shape around the center of the pan is provided on the center side of the dimple formation portion (see, for example, Patent Document 1).

JP2013-102925A (FIG. 1 etc.)

  In a conventional cooking device as described in Patent Document 1, a dimple shape that promotes the formation of boiling nuclei at the bottom of the pan and a wall portion formed in an annular shape to raise bubbles generated in the dimple are provided. It was set as the structure which produces | generates a crab hole in the approximate center part of the pan at the initial stage of the upper process.

  The bottom and side surfaces of cooking containers such as pots are usually made with as few irregularities as possible from the viewpoint of cleanability. Providing irregularities such as dimples inside the pan may cause dirt during the cleaning operation of the pan, or may become a base point for paint peeling.

Further, when the pan-like container is produced by sheet metal pressing, the unevenness such as dimples is pressed to push up the bottom surface, and the distance from the coil is increased. The fact that the distance from the coil increases means that it works in a direction that hinders the effect of induction heating, and there arises a problem that the heating efficiency is locally lowered and the temperature tends to decrease.
Further, when the pan-like container is generated by another molding means or a shaving process, the heat capacity is increased only in the uneven portions such as dimples. For this reason, there still arises a problem that the temperature tends to decrease locally and relatively.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an induction heating cooker that can be locally boiled without impairing the cleanability.

An induction heating cooker according to the present invention includes a main body and a pan base material that transmits a magnetic field line, and is detachably accommodated in the main body. The pan-shaped container is provided in the main body and guides the pan-shaped container. heating means for heating is disposed on the inner surface of at least the pot-shaped container has a hard magnetic material passes through the magnetic field lines than the pot base, the Nabemotozai is composed mainly of carbon burnt It consists of a ligation .

  According to the induction heating cooker of the present invention, since the magnetic material that absorbs the magnetic lines of force and easily generates heat is installed for the pan-like container that easily transmits the magnetic lines of magnetic force, the magnetic material generates heat locally. Thus, it is easy to form boiling nuclei and to easily generate a passage for steam at the time of boiling.

It is a perspective view showing roughly an example of composition of an induction heating cooking appliance concerning an embodiment of the invention. It is principal part sectional drawing which shows the principal part cross section of the induction heating cooking appliance which concerns on embodiment of this invention. It is a schematic diagram which shows typically the magnetic force line which permeate | transmits the pan of the induction heating cooking appliance which concerns on embodiment of this invention. It is a schematic diagram which shows typically the magnetic force line which permeate | transmits the pan of the induction heating cooking appliance which concerns on embodiment of this invention. It is a schematic diagram which shows typically the state at the time of the boiling bubble production | generation of the induction heating cooking appliance which concerns on embodiment of this invention. It is a top view which shows the example of arrangement | positioning of the magnetic material of the pan of the induction heating cooking appliance which concerns on embodiment of this invention. It is a top view which shows another example of arrangement | positioning of the magnetic material of the pan of the induction heating cooking appliance which concerns on embodiment of this invention.

  Hereinafter, embodiments of an induction heating cooker according to the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below. Moreover, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one.

  FIG. 1 is a perspective view schematically showing an example of a configuration of an induction heating cooker (hereinafter referred to as a heating cooker 100) according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a main part showing a cross-section of the main part of the heating cooker 100. Based on FIG.1 and FIG.2, the structure and operation | movement of the heating cooker 100 are demonstrated. This heating cooker 100 is an induction heating cooker in which a pot-like container (pot 5) containing an object to be heated (rice, water, etc.) is inserted and an eddy current is induced in the pot 5 to heat it.

  The heating cooker 100 includes a main body 1. Inside the main body 1, a pan 5 in which an object to be heated 15 can be put and cooked can be detachably accommodated. That is, the main body 1 is formed with an opening into which the pan 5 can be inserted. And the outer cover 2 covers the opening part of the main body 1 so that opening and closing is possible from the upper surface. When the outer lid 2 is closed, the outer lid 2 is hooked by a locking portion provided in the main body 1 and closed. Then, when the outer cover 2 closes the opening of the main body 1 and the locking part is released, the outer cover 2 opens upward with a hinge (not shown) as a fulcrum.

  An operation panel 3 is provided on the upper surface of the outer lid 2. The operation panel 3 is used to set and input the heating time and finish of the heating cooker 100, and to display the setting and operating state. The operation panel 3 transmits a control signal corresponding to the set content to a control device (not shown). The control device controls the heating state of the heating cooker 100 based on the received control signal. Specifically, the control device instructs the heating means such as the heating coil 10 to be described later on the heating amount and time, and performs heating cooking so as to achieve an appropriate cooking finish. Note that the operation portion and the panel portion of the operation panel 3 may be provided separately.

  A vapor cartridge 4 is detachably attached to the outer lid 2. The steam cartridge 4 has an action of escaping steam generated when the heated object 15 inside the main body 1 is heated, and an action of returning to the heated object side upon receiving the condensed water of the steam or the blown-down of the heated object. Have.

  The pot 5 is a substantially cylindrical container having an opening only on the upper surface and a thickness of approximately 5 mm. The opening-side end portion has a flange, and is configured with consideration given to ease of holding and storage. The user puts the object to be heated 15 into the pan 5 and performs heating. Examples of the object to be heated 15 include cooked rice composed of water and rice, and curry composed of meat, vegetables, and liquid and seasonings, but the cooking species is not particularly limited.

  A pan temperature sensor 6 is provided outside the bottom of the pan 5. The pan temperature sensor 6 is configured by a thermistor as an example, and is urged upward by a spring from the bottom surface of the main body 1 so as to contact the pan 5 and detect the temperature of the pan 5. The pan temperature sensor 6 transmits a detected voltage as a signal to a control device (not shown) according to the temperature. The control device applies the heat source feedback to the target temperature of the pan 5 by estimating the temperature of the pan 5 from the acquired detection voltage. By doing so, it plays the role of making the article 15 to be heated a desired finish.

  An inner lid 7 is installed on the main body 1 side of the outer lid 2. Specifically, the inner lid 7 is detachably installed on the outer lid 2 so as to face the pan 5 side. The inner lid 7 may be given water repellency by applying fluorine processing so that it can be washed with water when it becomes dirty due to the adherence of the article 15 to be heated.

  A lid packing 8 is provided on the outer periphery of the inner lid 7. The lid packing 8 has an action of contacting and sealing the flange portion of the pan 5 and the inner lid 7. That is, the lid packing 8 plays a role of avoiding a decrease in efficiency due to steam leakage or heat leakage from the side surface of the main body 1 and avoiding the danger of high-temperature steam contact with the user.

  A heating coil 10 serving as a heating means is provided on the outside of the bottom of the pan 5. The heating coil 10 is supplied with a high-frequency current from an inverter circuit (not shown), and generates a high-frequency magnetic field, thereby exciting the surface facing the heating coil of the pan 5 magnetically coupled to the heating coil 10. Eddy currents are induced. Joule heat is generated by the eddy current and the resistance of the pan 5, and the bottom surface of the pan 5 generates heat and is heated.

  A coil base 9 is installed inside the main body 1. The coil base 9 is configured such that the outside can fix the heating coil 10, and the inside can store the pot 5.

  The pan 5 and the object to be heated 15 are also heated from a lid heater 11 provided on the inner lid 7 and a body heater 12 provided on the coil base 9.

  The lid heater 11 is provided between the outer lid 2 and the inner lid 7 and is composed of a nichrome wire or the like, and heats the object to be heated 15 or the pan 5 from above. The lid heater 11 has a smaller output than the output of the heating coil 10 for heating the bottom surface of the pan 5 and is used as an auxiliary heating source. The lid heater 11 also has an effect of reducing condensed water adhering to the inner lid 7.

  The body heater 12 is provided on the outside of the coil base 9 and is composed of a nichrome wire or the like, and heats the pan 5 and the object to be heated 15 from the side surface. Like the lid heater 11, the body heater 12 is an auxiliary heating source, but since the distance to the pan 5 is short, the effect of heating the pan 5 and the object to be heated 15 is higher than that of the lid heater 11.

Next, the structure and heating operation of the pan 5 will be described.
The pan 5 has a pan base material that easily transmits magnetic lines of force. The pan base is composed of a non-magnetic, high-resistance carbon sintered body (a sintered body containing carbon as a main component). The carbon sintered body has a relative magnetic permeability of about 1 and is likely not suitable for induction heating, but has a resistivity equivalent to SUS304 (7.2 × 10 ⁻⁷ Ωm). As represented by the formula (1), electromagnetic induction heating can be sufficiently performed by appropriately selecting a coil current, a frequency, and the like as the electric power to the pot 5 to be charged. In addition, since the carbon sintered body has good thermal conductivity, the temperature of the pan easily rises uniformly in a short time.

  By the way, as an important index used when examining induction heating, there is a current penetration depth. The point at which the current density decreases 0.368 times due to the skin effect of eddy current is the penetration depth, and a larger value means that the material to be heated is more easily heated. The current penetration depth can be expressed by Equation (2).

  Here, when it is assumed that the frequency is 20 kHz, the current penetration depth of the carbon sintered body constituting the pan 5 of the heating cooker 100 is 11 mm from the equation (2). When the pan thickness of the pan 5 is 5 mm, it can be seen that there is a relationship of “penetration depth”> “pan thickness”. That is, it can be seen that the lines of magnetic force in the magnetic coupling are in a state in which the entire amount of heat generated by the carbon sintered pot 5 is not used as heat generation, in other words, the lines of magnetic force penetrate.

  3A and 3B are schematic diagrams for explaining magnetic lines of force that pass through the pan 5 of the heating cooker 100. FIG. FIG. 3A shows magnetic lines of force that pass through the pan 5 when no magnetic material is installed in the heating cooker 100. FIG. 3B shows magnetic lines of force that pass through the pan 5 when a magnetic material is installed in the heating cooker 100. Based on FIG. 3A and 3B, the magnetic force line which permeate | transmits the pan 5 of the heating cooker 100 is demonstrated in detail. The arrows shown in FIGS. 3A and 3B represent the lines of magnetic force 16.

  FIG. 3A shows that a magnetic field is generated around the current of the heating coil 10 (lines of magnetic force 16 shown in FIG. 3A). The magnetic field lines 16 pass through the wall surface of the pan 5 and pass through to the inside of the pan 5.

  As shown in FIG. 3B, the heating cooker 100 is configured to install a magnetic material 14 on the inner surface of the pan 5. The magnetic material 14 is comprised with the material which is hard to permeate | transmit a magnetic force line rather than a pan base material. Examples of the magnetic material 14 include ferrite, a mixed metal powder containing ferrite, or a stainless steel material having magnetism. Alternatively, the magnetic material 14 may be made of iron powder or the like. In addition, the material which is hard to permeate | transmit a magnetic field line compared with a pan base material is a material whose permeability is smaller than a pan base material.

  As shown in FIG. 3B, the magnetic force lines 16 that have passed through the base material of the pan 5 have a distribution that causes the magnetic material 14 located on the inner surface of the pan 5 to generate heat. Since the penetration depth of the magnetic material 14 is 1 mm or less to several μm, it is possible to generate heat using the magnetic force lines 16 effectively by installing a substantially thin magnetic material.

  Magnetic material 14 is a method of painting after applying blasting to the surface of pan 5, a method of vapor deposition or welding using a sprayer or sputtering, a method of adhering a sheet-like magnetic material with an adhesive, It can be installed by applying a method of providing an installation portion on the surface of the pan 5 and fitting and joining them.

  A protective coating 13 is provided on the inner surface of the pan 5 and above the magnetic material 14. The protective coating 13 is made of, for example, fluorine coating. By providing the protective coating 13, the water repellency inside the pot 5 can be increased to ensure ease of cleaning for the user, and the base material and the magnetic material 14 of the pot 5 can be protected. Since the magnetic material 14 can have an extremely thin structure (20 to 30 μm), even if the protective coating 13 having a thickness of 50 to several hundred μm is formed on the upper layer, the influence on the fixing property is small. Further, in actual use, the inside of the pan 5 can be configured so as not to have a level difference (that is, smooth). Therefore, the magnetic material 14 can be applied without impairing the user's cleanability.

  FIG. 4 is a schematic diagram schematically showing the state of the cooking device 100 when boiling bubbles are generated. Based on FIG. 4, the state at the time of the boiling bubble production | generation of the heating cooker 100 is demonstrated.

  The magnetic material 14 has a very small current penetration depth (1 mm or less to several μm) and absorbs the magnetic force lines 16 passing through the pan 5 to generate heat. Therefore, the location where the magnetic material 14 is installed becomes hotter than the location where the magnetic material 14 is not installed. As heating is continued, rising convection is promoted from the high temperature portion, and when rising to near the boiling temperature, the boiling bubbles 17 are locally generated above the saturation temperature (local boiling).

  The boiling bubbles 17 have a stirring effect on the object to be heated 15. In addition, the boiling foam 17 contributes to the formation of a so-called “crab hole” at the end of cooking for food such as cooked rice where the liquid is finally substantially lost. When the “crab hole” is formed, steam can be passed from the bottom of the pan 5 to the top, promoting heat transfer by steam and the removal of moisture that tends to remain on the bottom of the pan 5, thereby improving the finish of the food. It will have the effect of improving further.

  FIG. 5 is a top view showing an arrangement example of the magnetic material 14 of the pan 5 of the heating cooker 100. FIG. 6 is a top view showing another arrangement example of the magnetic material 14 of the pan 5 of the heating cooker 100. FIG. 5 shows a state in which the magnetic material 14 is randomly arranged. FIG. 6 shows a state in which the magnetic material 14 is arranged circumferentially and periodically. Based on FIG.5 and FIG.6, the effect at the time of arrange | positioning the magnetic material 14 at random is demonstrated.

  As shown in FIG. 5, the portion to be efficiently heated (that is, the portion where the magnetic material 14 is installed and the portion serving as the boiling core) is randomly placed inside the pan 5, so that the object to be heated 15 is boiled. The convection can be configured in a turbulent manner, and for example, an effect of enhancing the penetration of taste to the food, the uniformity of taste, and the like can be obtained.

  Moreover, as shown in FIG. 6, it is also possible to arrange the magnetic material 14 circumferentially and periodically. By arranging circumferentially and periodically the part that becomes high temperature (that is, the part where the magnetic material 14 is installed and the boiling core), the convection that rises from the bottom center of the pan 5 and flows to the side surface, or conversely, It is possible to realize convection that flows in a direction from the upper part of the side surface to the center of the bottom surface, and it is possible to realize convection in a desired direction. For example, in the case of noodle bowls, the noodles are moved by convection, so that the noodles can be heated efficiently without the problem of the noodles solidifying in a dumpling form.

  Arranging the magnetic material 14 in a circumferential shape means arranging the magnetic material 14 in a ring shape. Arranging the magnetic material 14 periodically means arranging the magnetic material 14 having a similar shape in the circumferential direction at a predetermined interval. FIG. 6 shows an example in which the magnetic material 14 is circumferentially and periodically arranged, but the magnetic material 14 may be circumferentially or periodically arranged.

  As an application example of the present invention, the present invention can be applied to commercial and household induction heating cookers having pan-shaped containers.

  1 body, 2 outer lid, 3 operation panel, 4 steam cartridge, 5 pan, 6 pan temperature sensor, 7 inner lid, 8 lid packing, 9 coil base, 10 heating coil, 11 lid heater, 12 trunk heater, 13 protective coating , 14 Magnetic material, 15 Object to be heated, 16 Magnetic field lines, 17 Boiling foam, 100 Heating cooker.

Claims (8)

The body,
It is composed of a pan base material that transmits magnetic lines of force, and a pan-like container that is detachably accommodated in the main body,
A heating means provided on the main body for inductively heating the pan-like container;
A magnetic material that is installed at least on the inner surface of the pan-like container and is less likely to transmit lines of magnetic force than the pan base ;
The pan base material is
An induction heating cooker comprising a sintered body containing carbon as a main component . The thickness of the pan base is
The induction heating cooker according to claim 1 , wherein the induction heating cooker is thinner than a current penetration depth of the pan base material. The magnetic material is
The induction heating cooker according to claim 1 or 2 , wherein the induction heating cooker is installed on an inner surface of the pan-like container by any one of painting, vapor deposition, adhesion, and bonding. The induction heating cooker according to any one of claims 1 to 3 , wherein a protective coating having water repellency is provided on an upper layer of the magnetic material. The protective coating is
The induction heating cooker according to claim 4 , wherein the inside of the pan-like container is smoothed. The magnetic material is
The induction heating cooker according to any one of claims 1 to 5 , wherein the induction heating cooker is installed at a plurality of locations. The magnetic material is
The induction heating cooker according to claim 6 , wherein the induction heating cooker is randomly arranged. The magnetic material is
The induction heating cooker according to claim 6 , wherein the induction heating cooker is arranged in at least one of a circumferential shape and a periodic shape.

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