JP2010078207A - High frequency heating element and cooking appliance for high frequency heating apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein, since a conventional high frequency heating element comprises a magnetic material and rubber, when the temperature of the high frequency heating element is raised to a Curie temperature, the temperature rise speed is reduced due to reduction in magnetic loss, making it difficult to brown an object to be heated. <P>SOLUTION: This high frequency heating element 3 comprises at least: two types of high frequency absorbing materials having a heating mechanism by high frequency absorption different in a low temperature region and a high temperature region; and elastomer 7. Excellent heat generating performance is obtained thereby in a wide temperature range from the low temperature region to the high temperature region, and the temperature is raised to the use temperature of a heated object placement tray for a short time. Even if high frequency absorbing characteristics of either one of the two types of the high frequency absorbing materials are deteriorated, excessive decline in the heat generating performance is suppressed, to use the element as a cooking appliance for a high frequency heater for a long time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a high-frequency heating element that generates heat by a high frequency used in a microwave oven or the like, and a cooking utensil for a high-frequency heating device that can burn the surface of an object to be heated by high-frequency heating.

  Conventionally, as this type of high-frequency heating element and cooking utensils for high-frequency heating equipment, a high-frequency heating element mainly composed of a magnetic material is provided on the bottom surface of a heated object placing tray on which the heated object is placed. Yes (see, for example, Patent Document 1).

  FIG. 4 is a perspective view of a heated object placing tray 31 provided with a conventional high-frequency heating element described in Patent Document 1. As shown in FIG. The high-frequency heating element is provided on the bottom surface (not shown) of the heated object placing tray 31.

  FIG. 5 is a partial cross-sectional view of the article to be heated 31 on which the high-frequency heating element 32 is provided. As shown in FIG. 5, the high-frequency heating element 32 is provided on a painted metal base material 33 that constitutes the article to be heated 31. The high-frequency heating element 32 includes particles of a high-frequency absorption material mainly composed of a magnetic material with spherical particles having a Curie temperature of 200 to 300 ° C. and a rubber material. The particles of the high-frequency absorption material are contained in the rubber material. It is in a uniformly dispersed state.

  When the object to be heated is placed on a predetermined position of a high-frequency cooking device equipped with a magnetron that generates a high frequency and grill cooking is started, the high-frequency wave oscillated from the magnetron is applied to the object to be heated. The high-frequency heating element 32 provided on the mounting tray 31 absorbs the heat to convert it into heat, and the heated object mounting tray 31 is heated. And the to-be-heated object which is contacting the heated to-be-heated object mounting tray 31 is heated, and a to-be-heated object becomes burnt with progress of cooking.

  Generally, when performing grill cooking, if it is going to make the deliciousness of the cooking thing which is a to-be-heated object suitable, and a suitable burnt, it changes with the kind and quantity of a to-be-heated object, but the to-be-heated object mounting tray 31 is 150-. It is necessary to raise the temperature to 300 ° C. in a short time.

Further, as another applicable material of the high-frequency heating element 32, there is a composition of magnetite and elastomer (see, for example, Patent Document 2).
JP 2007-225186 A JP 2007-45975

  However, the conventional high-frequency heating element 32 uses a high-frequency absorption material mainly composed of a magnetic material having a Curie temperature of 200 to 300 ° C. The high-frequency absorbing material made of this magnetic material has a high magnetic loss at low temperatures, so the high-frequency absorption efficiency is high and the heat is quickly generated and the temperature rises.However, when the temperature becomes close to the Curie temperature, the magnetic material undergoes a magnetic phase transition. The magnetic loss, which is one of the magnetic characteristics, is reduced, the high-frequency absorption characteristics are lowered, and the temperature rise rate near the Curie temperature is slow.

In addition, when a high-frequency heating element made of a high-frequency absorption material mainly composed of a magnetic material having a Curie temperature of 200 to 300 ° C. is used as a tool for a high-frequency heating device, it is short for scoring suitable for an object to be heated. Although it is necessary to raise the temperature of the heated object placing tray over time, the temperature rising rate of the heated object placing plate is slowed by the fact that the high frequency absorption characteristics of the high frequency absorbing material are reduced near the Curie temperature. It takes time to burn the object to be heated appropriately, and the cooking time becomes longer, the overheating state of the object to be heated due to the longer cooking time occurs, and the moisture content inside the object to be heated decreases. However, there was a problem that the taste was lost.

On the other hand, there is magnetite (Fe ₃ O ₄ ) as a magnetic material having a high Curie temperature. Magnetite has a high Curie temperature of 580 ° C., and no magnetic phase transition occurs at 300 ° C., but oxidation proceeds rapidly at temperatures of 200 ° C. or higher, and the crystal structure of hematite (Fe ₂ O ₃ ) has low high-frequency absorption characteristics. Changes. Therefore, although magnetite has a high initial high-frequency absorption characteristic, the high-frequency absorption characteristic gradually deteriorates due to oxidation, so that there is a problem that stable temperature rise performance cannot be obtained in the long term.

  In addition, when a high-frequency heating element made of a high-frequency absorbing material mainly composed of magnetite is used as a device for a high-frequency heating device, the temperature rise performance of the high-frequency heating element changes with time, so the initial condition of the object to be heated The suitable burnt eyes cannot be reproduced in long-term use, leading to user dissatisfaction.

  Furthermore, when trying to obtain suitable burnished eyes, it is necessary to perform manual cooking from automatic cooking, and the operation of the cooking equipment becomes complicated, and when the burnished items are given priority, the inside of the heated object is overheated and the heated object is heated. There was a problem that the taste was lost.

  In addition, in the combination of magnetite and silicon rubber, a cross-linking reaction of silicon rubber occurs by magnetite in a high temperature environment, and a phenomenon that silicon rubber contracts and hardens occurs. As a result, the high-frequency heating element is peeled off from the object tray due to contraction and cracks are generated due to hardening, and the function as the high-frequency heating element is lost, and the durability and reliability as a cooking utensil for high-frequency heating equipment are lost. Had the problem of being inferior.

  The oxidation of magnetite involves oxygen in the air, diffusion of water vapor generated during cooking, contact with water used when washing and cooling the object to be heated at a high temperature, It occurs by reaction with oxygen atoms.

  The present invention solves the above-mentioned conventional problems, improves the temperature rise performance of the high-frequency heating element, can realize a cooking state in which the taste of the object to be heated and appropriate burnt are made compatible, and An object of the present invention is to provide a high-frequency heating element capable of preventing exfoliation and cracking of the heating element and improving excellent durability and reliability, and a cooking utensil for a high-frequency heating apparatus using the same.

  In order to solve the above-described conventional problems, the high-frequency heating element of the present invention is composed of at least two types of high-frequency absorbing materials having different heat generation mechanisms by high-frequency absorption in a low temperature region and a high temperature region.

  As a result, the heat generating mechanism of the high-frequency heating element is different between the low-temperature region and the high-temperature region, so that excellent heat generation performance can be obtained by absorbing high-frequency over a wide range of temperatures, and the operating temperature of the heated object tray can be increased in a short time. Since it can be heated and is composed of at least two types of high-frequency absorption materials, even if one of them deteriorates the high-frequency absorption characteristics due to some action, if the other does not deteriorate, the heat generation performance is extremely lowered. It can be suppressed and can be used as a cooking utensil for a high-frequency heater over a long period of time.

The cooking device for a high-frequency heater according to the present invention is provided with the high-frequency heating element according to the present invention on a metal heated object mounting tray on which a coating layer containing an organic polymer is placed. It is made into the structure.

  As a result, the high-frequency heating element always has a stable and high temperature raising performance, and the metal heated object mounting tray provided with the high-frequency heating element has excellent thermal conductivity. Since the generated heat can be efficiently transferred to the object tray, the object to be heated can be appropriately burned in a short time and the water inside the object to be heated can be reduced. Overheating is prevented, and the deliciousness of the object to be heated can be realized.

  The high-frequency heating element of the present invention and the cooking utensil for a high-frequency heating device using the same can be heated to a working temperature in a short time by using a high-frequency absorbing material having a different heating mechanism in a low temperature region and a high temperature region.

  In addition, by configuring the high-frequency heating element with a plurality of high-frequency absorbing materials, even if one of the high-frequency absorption characteristics is deteriorated, it is possible to prevent an extreme decrease in the heat generation performance of the high-frequency heating element. It can be used as a cooking utensil for a high-frequency heater.

  Furthermore, since overheating of the object to be heated can be prevented, a new cooking method that achieves both deliciousness and moderate burn can be realized.

  In the first invention, the high-frequency heating element is composed of at least two types of high-frequency absorbing materials and elastomers that have different heat-generating mechanisms by high-frequency absorption in the low-temperature region and the high-temperature region, thereby obtaining excellent heat generation performance in a wide range of temperatures. It can be heated up to the working temperature of the dish to be heated in a short time and is composed of at least two types of high-frequency absorbing materials. Even if it deteriorates, it can suppress the fall of extreme heat generation performance, and can be used as a cooking utensil for a high-frequency heater over a long period of time.

  In the second invention, in particular, the high-frequency absorbing material having a different heat generation mechanism of the first invention is composed of a magnetic material and a semiconductor material. The rise of the temperature of the high-frequency heating element can be made faster. On the other hand, in the high temperature region, the high frequency heating element rises in temperature, and near the Curie temperature, the magnetic loss of the magnetic material decreases and the heat generation performance decreases, but in the high temperature region, the dielectric loss of the semiconductor material contained in the high frequency heating element, Because it absorbs high frequency efficiently due to resistance loss and generates heat, fast temperature rising performance in the low temperature region can be maintained even in the high temperature region, and high frequency heating consisting of a heated object placing tray provided with a high frequency heating element The cooking utensil for equipment can be raised to the working temperature in a short time.

  In the third invention, since the semiconductor material of the second invention has a structure in which the needle-shaped particles are in contact with each other by using the needle-shaped particles as the semiconductor material of the second invention, when the temperature rises, the characteristics as a semiconductor Eddy currents flow through the needle-shaped particles, generating Joule heat. This Joule heat is added to the absorption and heat generation of high frequency due to dielectric loss, and higher temperature rise performance can be obtained.

In the fourth invention, in particular, by using ceramic whiskers or fibers as the semiconductor material of the second invention, the aspect ratio of the particles of the semiconductor material can be increased in addition to the effects of the third invention. The number of contact points between the particles of the high-frequency absorbing material increases. As a result, the amount of the high-frequency absorbing material used can be reduced, and the cost can be reduced. In addition, since the semiconductor material is ceramic, chemical stability against water, water vapor, and acid and alkali components contained in oils and fats generated during cooking is high, and durability and reliability of the high-frequency heating element can be improved.

  The fifth invention is particularly a ceramic material comprising zinc oxide, silicon carbide, and a metal thin film layer as a whisker or fiber of the ceramic of the fourth invention, and a ceramic containing silicon and titanium or zirconium and carbon and oxygen. By using at least one of the materials, particularly suitable dielectric properties of these materials and appropriate conductivity expressed by characteristics as a semiconductor are suitable for high-frequency absorption, and high-frequency temperature rise performance can be obtained.

  The sixth invention, in particular, uses magnetite as the magnetic material of the second invention, and has an excellent temperature rise performance in a low temperature region due to its high Curie temperature and higher absorption of high frequency. Obtainable. On the other hand, if the magnetite is exposed to a high temperature atmosphere of 200 ° C. or higher for a long time, the structure changes due to oxidation and the high-frequency absorption characteristics deteriorate, so the temperature rise characteristics also deteriorate. Incorporation of a stable semiconductor material makes it possible to compensate for high-frequency absorption in a low-temperature region, so it is possible to suppress a decrease in temperature rise performance as a high-frequency heating element, and to have excellent temperature rise characteristics over a long period of time Can be realized.

  In the seventh invention, in particular, by using silicon rubber or fluororubber as the elastomer of any one of the second to sixth inventions, since they have excellent heat resistance and chemical resistance, they are durable. A highly reliable high-frequency heating element can be realized. In addition, the structure of the high-frequency absorbing material particles dispersed in the elastomer prevents the high-frequency heating element from dropping or breaking even when subjected to mechanical shock due to external force or dropping or thermal shock due to repeated cold heat. can do.

  In an eighth aspect of the present invention, as a cooking utensil for a high-frequency heating device, a heated object placing dish on a metal heated object placing dish on which a coating layer containing an organic polymer is placed. By providing the high-frequency heating element according to any one of the first to seventh inventions on a part of the surface on which the object to be heated is not placed, it is possible to always achieve a stable and high temperature raising performance. Moreover, since the metal heated object mounting tray provided with the high frequency heating element has excellent thermal conductivity, the heat generated by the high frequency heating element can be efficiently transmitted to the heated object mounting dish. In addition to being able to burn the object to be heated in a short time, overheating of the object to be heated can be prevented, and moisture inside the object to be heated can be maintained, and both deliciousness and moderate burn can be achieved. A new cooking method can be realized.

In the ninth aspect of the invention, in particular, in the high-frequency heating element of the eighth invention, the area of the high-frequency heating element provided on the metal heated object mounting tray is set to 0.1 m ² or less, so that predetermined power consumption is achieved. With this high frequency, the object to be heated and the object to be heated can be heated to a predetermined temperature in a short time, thereby shortening the cooking time and saving energy.

  In the tenth aspect of the invention, in particular, the heat transfer to the dish to be heated due to the increase of the film thickness by setting the film thickness of the high-frequency heating element of the eighth or ninth invention to 0.5 to 2 mm. And a decrease in the heating rate due to an increase in the heat capacity of the high-frequency heating element itself, and a decrease in the high-frequency absorption characteristics of the high-frequency heating element due to the thin film thickness can be suppressed. The heat generated by the heating element absorbing the high frequency can be efficiently transmitted to the object to be heated and the object to be heated, and cooking time can be shortened and energy can be saved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the present embodiment. In addition, a configuration unique to each embodiment can be combined as appropriate.

(Embodiment 1)
FIG. 1 shows a cross-sectional view of a cooking utensil for a high-frequency heating device provided with a high-frequency heating element according to the first embodiment of the present invention.

  In addition, the form of FIG. 4 described by the prior art example is applied to the to-be-heated object mounting dish used as a cooking appliance for this invention high frequency heating equipment.

  In FIG. 1, a cooking utensil 1 for high-frequency heating equipment includes a metal heated object placing tray 2 on which a coating layer containing an organic polymer is formed, and a part of the lower surface of the heated object placing dish 2. The high-frequency heating element 3 is provided. Moreover, the fixing member 4 for arrange | positioning in the predetermined | prescribed position in the store | warehouse | chamber of high frequency heating apparatuses, such as a microwave oven, is attached to the both ends of the to-be-heated material mounting tray 2. As shown in FIG. The fixing member 4 not only has a function of positioning the object to be heated mounting tray 2 but also a handle function when carrying and taking out, and the metal object to be heated mounting dish 2 in the high frequency overheating device. It has a function of preventing sparks when placed and fed with high frequency power.

  FIG. 2 is a schematic diagram showing the structure of the high-frequency heating element 3.

  In FIG. 2, the high-frequency heating element 3 includes magnetic material particles 5, semiconductor material particles 6, and an elastomer 7, and the magnetic material particles 5 and the semiconductor material particles 6 are dispersed in the elastomer 7. ing.

Examples of the magnetic material applied as the high-frequency heating element 3 include those containing as a main component at least one of Mn—Zn, Mg—Zn, Ni—Zn, and magnetite (Fe ₃ O ₄ ). Among them, magnetite that is excellent in high-frequency absorption due to magnetic loss is useful.

  The particles 6 of the semiconductor material have a needle shape and are dispersed in the elastomer 7 with some of the particles in contact with some of the other particles. As the semiconductor material in which the shape of the particles is needle-like, whiskers and fibers made of a ceramic material having a high dielectric loss and high resistance loss, which are advantageous for high-frequency absorption, are applied. Particularly useful are ceramic materials such as zinc oxide, silicon carbide, and titanium oxide with a metal thin film layer formed thereon, and ceramic materials containing silicon, titanium or zirconium, carbon, and oxygen.

  The elastomer 7 is made of silicon rubber or fluoro rubber that has excellent heat resistance under a temperature environment of 250 to 300 ° C., chemical resistance such as seasonings and water vapor, mechanical shock, and heat shock. The main component is applied.

  Next, an embodiment of a method for producing the high frequency heating element 3 of the present invention will be described.

  The magnetic material particles 5, the semiconductor material particles 6, and the elastomer 7, which are high-frequency absorbing materials, are mixed into the elastomer 7 using a kneading apparatus such as an open roll or a kneader. The mixture is kneaded until it is uniformly dispersed, and then a cross-linking agent is added as necessary and kneaded again. Next, a necessary amount of the kneaded material lump or the one that has been dispensed into a sheet with an open roll is collected, and placed on the surface of the object to be heated 2 on which the object to be heated is not placed. Perform pressure bonding and primary vulcanization. Thereafter, the cooking utensil 1 for the high-frequency heating device of the present invention in a state where the high-frequency heating element 3 is formed on the article to be heated 2 is obtained by performing heat treatment such as secondary vulcanization as necessary.

  During kneading, a heat-resistant agent for imparting further heat resistance of the high-frequency heating element 3, an anti-aging agent, an oil and fat agent for imparting flexibility, and the like may be added as necessary.

  Moreover, in order to improve the adhesiveness between the high-frequency heating element 3 and the heated object placing tray 2, the bonding surface of the high-frequency heating element 3 or the surface on which the high-frequency heating element 3 of the heated object placing dish 2 is provided. In addition, a primer having an adhesion function may be applied, and the article to be heated 2 and the high-frequency heating element 3 may be adhered via the primer, or the magnetic material particles 5 and the semiconductor material particles 6 may be bonded in advance. An adhesive may be added during kneading of the elastomer 7 and the elastomer 7.

  FIG. 3 is a cross-sectional view of a high-frequency heating cooker on which the cooking utensil 1 for high-frequency heating equipment according to the present invention is mounted.

  In FIG. 3, the heating chamber 9 takes in and out the right wall 10, the left wall 11, the back wall 12, the upper wall 13, the bottom wall 14, and the object to be heated, which are metal boundaries composed of a metal material. An open / close door (not shown), which is an open / close wall surface, is formed in a substantially rectangular parallelepiped shape, and is formed so as to substantially confine the supplied high-frequency inside. The bottom wall surface 14 is provided with a narrowed section 15 having a substantially rectangular cross section, and a high-frequency excitation section 16 that feeds power into the heating chamber 9 is disposed at a substantially central portion of the narrowed section 15.

  The magnetron 17 which is a high frequency generating means generates a high frequency to be fed to the heating chamber 9, and a waveguide 18 is provided between the magnetron 17 and the excitation unit 16 in order to guide the high frequency generated from the magnetron 17 to the excitation unit 16. Is provided. The excitation unit 16 is provided with an antenna 19 that extends into the waveguide 18 and is coupled to a high frequency transmitted through the waveguide 18, and one end of the antenna 19 is a radiating antenna having a waveguide type directivity. The radio wave radiation means 20 is connected.

  The other end of the antenna 19 is assembled by inserting and assembling an output shaft of a motor 21 that is a driving means for rotating the radio wave radiating means 20. The radio wave radiating means 20 is driven to rotate by driving the motor 21 so that the fan-shaped upper surface is substantially parallel to the bottom surface of the diaphragm 15.

  Further, a sealing means 22 made of a radio wave transmitting material, for example, a glass-based or ceramic-based material, is provided at the opening of the aperture 15.

  In addition, a heater 23 is provided in the upper part of the heating chamber 9, and a convection heater unit (not shown) is provided in the back of the back wall surface 12, and functions of high-frequency cooking, grill cooking, and oven cooking of the heated object. It has the composition which has.

  The cooking utensil 1 for a high-frequency heating device is inserted and attached into the heating chamber 9 along a rail portion 24 which is a locking means provided on the right wall surface 10 and the left wall surface 11 of the heating chamber 9.

  The heating chamber 9 is provided with a thermistor 25 that detects the temperature in the heating chamber 9 and an infrared sensor 26 that detects the temperature of the object to be heated, the cooking utensil 1 for high-frequency heating equipment, and the like.

  Next, the operation and action of the cooking utensil 1 for a high-frequency heating device of the present invention will be described using the high-frequency heating cooker having the above configuration.

  When a predetermined instruction operation is performed in a state where the cooking utensil 1 for a high-frequency heating device in which an object to be heated is placed in the heating chamber 9 is locked to the rail portion 24 and the open / close door is closed, the magnetron 17 is controlled by the control means 27. Operates to generate high frequency. The generated high frequency passes through the waveguide 18 and the excitation unit 16, passes through the sealing means 22 made of ceramic or the like from the radio wave emission means 20, and is fed into the heating chamber 9.

The high frequency fed into the heating chamber 9 is absorbed by the high frequency heating element 3 constituting the cooking utensil 1 for high frequency heating equipment and converted into heat. The heat is transmitted to the heated object placing tray 2 constituting the cooking utensil 1 for high frequency heating equipment, and the heated object in contact with the heated object placing dish 2 is heated.

  In general, when grill cooking is performed, if an attempt is made to achieve both the deliciousness of the cooked food to be heated and a suitable burnt, the heated object placing plate is 150 to 300 depending on the type and amount of the heated object. It is necessary to raise the temperature to a temperature of ° C in a very short time.

  Conventionally, a Mn—Zn magnetic material is used as a high-frequency absorbing material for a high-frequency heating element. The Curie temperature of this magnetic material is 200 to 300 ° C., although it varies depending on the composition. The heat generation mechanism of the magnetic material is mainly due to magnetic loss of the material, has high frequency absorption characteristics in a low temperature region, and has a higher temperature rising rate than the semiconductor material. However, when the Curie temperature (near) is reached, the magnetic loss is reduced due to the magnetic phase transition, and the high-frequency absorption characteristics are lowered, so that the rate of temperature rise is significantly reduced in a high temperature region above the Curie temperature.

  As a result, it takes time to moderately burn the object to be heated, the cooking time becomes longer, the overheating state of the object to be heated occurs, the amount of moisture inside the object to be heated decreases, and the taste is delicious. Will be lost.

  On the other hand, in semiconductor materials such as silicon carbide and zinc oxide, the heat generation mechanism is mainly the dielectric loss and resistance loss of the material, and the rate of temperature rise is slower than that of the magnetic material in the low temperature region. However, in the high temperature region, the high-frequency absorption characteristics due to dielectric loss and resistance loss are higher than the high-frequency absorption characteristics due to magnetic loss, and as a high-frequency heating element, the temperature can be raised to a high temperature and a high temperature rise rate can be obtained.

  The high-frequency heating element 3 of the present invention pays attention to the fact that the heat generation mechanism by high-frequency absorption differs between the low temperature region and the high temperature region of the magnetic material and the semiconductor material. Realized high temperature rise performance.

  In other words, the high-frequency heating element 3 of the present invention comprises a high-frequency absorbing material having a different heating mechanism made of a magnetic material and a semiconductor material. The rise of body temperature can be made faster. On the other hand, the temperature of the high-frequency heating element 3 rises in the high temperature region, and the magnetic loss of the magnetic material decreases and the heat generation performance deteriorates near the Curie temperature. However, in the high temperature region, the semiconductor material contained in the high-frequency heating element 3 causes dielectric loss. Because the resistance loss absorbs the high frequency and generates heat, fast temperature rising performance in the low temperature region can be maintained even in the high temperature region, and excellent temperature rising performance can be realized in a wide range of temperatures.

  Therefore, by providing the object to be heated with the high-frequency heating element 3 of the present invention, the operating temperature can be raised in a short time, maintaining the deliciousness of the object to be heated, and imparting a suitable burn. Can do. In addition, even if the high-frequency absorption characteristics of either the magnetic material or the semiconductor material deteriorate due to some action, it can suppress an extreme decrease in heat generation performance and can be used as a cooking utensil for a high-frequency heater for a long time. it can.

  The high frequency heating element 3 of the present invention is composed of a high frequency absorbing material and an elastomer 7. With this configuration, the elastomer 7 can protect the magnetic material particles 5 and the semiconductor particles 6, which are high-frequency absorbing materials, and can realize strong adhesion to the heated object placing tray 2. In addition, it is possible to strengthen against a mechanical shock caused by dropping or a thermal shock caused by repeated cooling, and the high-frequency heating element 3 can be prevented from dropping or breaking.

Further, the shape of the particles 6 of the semiconductor material used for the high-frequency heating element 3 of the present invention is a needle shape, which is also a factor for improving the heating rate. As shown in FIG. 2, the needle-like semiconductor material particles 6 are dispersed in the elastomer 7 in contact with each other and connected to each other. This structure is considered to increase the high-frequency absorption characteristics and increase the heating rate of the high-frequency heating element 3.

  Although the reason for this is not clear, the needle-like semiconductor material particles 6 generate heat due to high-frequency absorption not only as dielectric loss but also as a semiconductor due to the rise in temperature due to the structure in which the particles are in contact with each other. Eddy currents flow through the needle-like particles, generating Joule heat due to resistance loss. This Joule heat is added to the high frequency absorption and heat generation due to dielectric loss, and it is considered that higher temperature rise performance can be obtained.

  As the semiconductor material used for the high-frequency heating element 3 of the present invention, ceramic whiskers or fibers are useful. Since the aspect ratio of the particles 6 of the semiconductor material can be increased, the number of contact points between the particles of the high-frequency absorbing material is increased. As a result, the amount of the high-frequency absorbing material used can be reduced and the cost can be reduced. In addition, since the semiconductor material is ceramic, chemical stability against water, water vapor, and acid and alkali components contained in oils and fats generated during cooking is high, and durability and reliability of the high-frequency heating element can be improved.

  Further, the ceramic whisker or fiber which is a semiconductor material is at least one kind of a ceramic material whose main component is a zinc oxide, silicon carbide, a metal thin film layer, or a ceramic material containing silicon and titanium or zirconium and carbon and oxygen. Can be used. These materials have a large dielectric loss, and a resistance loss due to appropriate conductivity that is manifested by characteristics as a semiconductor is suitable for high-frequency absorption, and the temperature raising performance of the high-frequency heating element 3 can be improved.

  As a magnetic material, there is magnetite having a Curie temperature of 500 ° C. or higher. This magnetite does not cause a magnetic phase transition at 300 ° C., and thus has a high temperature rising rate from a low temperature to a high temperature region. However, oxidation proceeds rapidly at a temperature of 200 ° C. or higher, and the crystal structure changes from magnetite to hematite with low high-frequency absorption characteristics. Therefore, when magnetite alone is used as the high-frequency absorbing material used for the high-frequency heating element, the initial high-frequency absorption characteristic is high, but the high-frequency heating element gradually changes with time in the direction in which the high-frequency absorption characteristic gradually decreases due to oxidation. As the temperature rise performance gradually decreases and the use time becomes longer, a burnt suitable for the object to be heated cannot be obtained.

  Depending on the type and chemical composition of the elastomer, magnetite accelerates the crosslinking reaction of an elastomer such as silicon rubber, and the high-frequency heating element peels off and cracks due to the curing of the elastomer.

  In the present invention, at least two types of magnetic material, magnetite and semiconductor material, are used as the high frequency absorbing material. As a result, the amount of magnetite can be reduced, so that even if the crystal structure due to oxidation changes, it is possible to suppress a decrease in high-frequency absorption characteristics compared to the case where magnetite is used alone, and the temperature rise in the low temperature region The ability to stop the performance slightly, and the coexistence of a semiconductor material with a stable crystal structure in a high-temperature environment can compensate for high-frequency absorption, resulting in excellent initial temperature rise performance over a long period of time. Can be maintained over time.

  Moreover, since the progress of the crosslinking reaction with the elastomer 7 such as silicon rubber can be slowed by reducing the amount of the magnetite particles of the high-frequency heating element 3, the peeling of the high-frequency heating element 3 by the curing of the elastomer 7, Generation of cracks can be prevented and high durability can be realized.

  As the elastomer 7 used in the high-frequency heating element 3 of the present invention, silicon rubber or fluorine rubber is preferable. Since these rubbers are excellent in heat resistance under a temperature environment of 300 ° C. as a cooking utensil for high-frequency heating equipment 1, chemical resistance such as seasonings and water vapor, mechanical impact resistance, and thermal shock resistance, The high-frequency heating element 3 having high durability and reliability can be realized.

  Moreover, the cooking utensil 1 for the high-frequency heating device of the present invention has the heat generated by the high-frequency heating element 3 because the heated object mounting tray 2 has excellent thermal conductivity. The heat can be efficiently transmitted to the article to be heated placing tray 2. Therefore, the to-be-heated object mounting tray 2 can be heated up to the cooking temperature of 150-300 degreeC in a short time, and a moderate burn can be attached to a to-be-heated object in a short time.

  Moreover, since the cooking utensil 1 for high-frequency heating equipment can prevent overheating of the object to be heated, it can hold moisture inside the object to be heated, which is necessary for deliciousness. A cooking method can be realized.

When the magnetron 17 is operated with a power consumption of 700 to 1000 W, if the area of the high-frequency heating element 3 provided in the metal heated object mounting tray 2 is 0.1 m ² or more, the heated object mounting dish 2 Since the heat capacity of the cooking utensil 1 itself for the high frequency heating device increases and the heat dissipation loss increases due to the expansion of the heat dissipation area due to the increase in the surface area, The speed becomes slow, and the optimum burnt and deliciousness of the heated object cannot be obtained.

Therefore, in order to obtain optimum burnt and deliciousness, it is desirable that the area of the high-frequency heating element 3 is 0.1 m ² or less. Moreover, since the to-be-heated material mounting tray 2 and the to-be-heated material mounted on it can be heated up to predetermined temperature in a short time by this, cooking time can be shortened and energy saving can be achieved.

  If the film thickness of the high-frequency heating element 3 is 2 mm or more, the heat capacity of the high-frequency heating element 3 is increased, the heating rate of the high-frequency heating element 3 is decreased, and the thermal resistance of the high-frequency heating element 3 is increased. Since the heat dissipation loss from the surface of the high-frequency heating element 3 is increased, the heat transfer due to heat conduction to the heated object placing tray 2 is reduced, and a fast temperature increase rate of the heated object placing plate 2 cannot be obtained. . Further, the cost increases due to the thick film thickness. On the other hand, if the film thickness of the high-frequency thermal heating element 3 is 0.5 mm or less, the content of the high-frequency absorbing material is reduced, the high-frequency absorption efficiency is lowered, and a high temperature rise rate cannot be obtained.

  Therefore, in order to efficiently transmit the heat generated by the high-frequency heating element 3 by absorbing the high frequency to the heated object placing tray 2 and the heated object, the thickness of the high-frequency heating element 3 is in the range of 0.5 to 2 mm. Is desirable. Thus, the heated object placing tray 2 and the heated object placed thereon can be heated to a predetermined temperature in a short time, and cooking time can be shortened and energy can be saved.

  When the content of the high-frequency absorbing material used in the high-frequency heating element 3 of the present invention is 20% by volume or less, the high-frequency absorption characteristics are deteriorated, and a satisfactory temperature rise performance as a high-frequency heating element cannot be obtained. If the volume is 60% by volume or more, the composite with the elastomer 7 becomes hard, the flow of the composite is poor during hot pressing, and the high-frequency heating element 3 with a uniform film thickness cannot be obtained. Since the film is hardened, the thermal shock resistance and mechanical shock resistance are reduced, and the repeated occurrence of falling or cooling may damage the high-frequency heating element 3.

  Therefore, in order to ensure excellent temperature rise performance, durability, and reliability, it is desirable that the content of the magnetite particles 5 on which the coating layer is formed be in the range of 20 to 60%.

  Further, the ratio of the magnetic material particles 5 and the semiconductor material particles 6 which are high-frequency absorbing materials is not particularly limited, and the high-frequency absorption characteristics of the magnetic material particles 5 and the semiconductor material particles 6 and the high-frequency heating device are not limited. It is set so as to realize an optimum temperature raising performance according to the size and weight of the cooking utensil 1 and the heat capacity, and is not particularly limited.

  As described above, since the high-frequency heating element of the present invention has excellent temperature rise performance, it can be applied not only as a heating element for cooking appliances but also as an industrial dryer or heating machine. Since it has excellent absorption characteristics, it can be applied as a radio wave sealing device by adding a cooling device.

Sectional drawing of the cooking utensil for high frequency heating appliances provided with the high frequency heating element in Embodiment 1 of this invention Schematic diagram showing the structure of the high-frequency heating element according to Embodiment 1 of the present invention. Sectional drawing of the high frequency heating cooking appliance with which the cooking appliance for high frequency heating equipment of this invention is mounted The perspective view of the to-be-heated material mounting tray provided with the conventional high frequency heating element Partial sectional view of a conventional dish to be heated

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cooking utensil for high frequency heating equipment 2 Heated object mounting plate 3 High frequency heating element 5 Magnetic material particle 6 Semiconductor material particle 7 Elastomer

Claims (10)

A high-frequency heating element that generates heat by absorbing high-frequency waves, and is composed of at least two types of high-frequency absorption materials and elastomers that have different heating mechanisms due to high-frequency absorption in a low temperature region and a high temperature region. The high-frequency heating element according to claim 1, wherein the high-frequency absorbing materials having different heating mechanisms are made of a magnetic material and a semiconductor material. The high-frequency heating element according to claim 2, wherein the semiconductor material has a needle shape. The high-frequency heating element according to claim 2, wherein the semiconductor material is a ceramic whisker or fiber. 5. The ceramic whisker or fiber is at least one of a ceramic material containing zinc oxide, silicon carbide, a metal thin film layer, and a ceramic material containing silicon and titanium or zirconium, carbon and oxygen. High frequency heating element. The high frequency heating element according to claim 2, wherein the magnetic material is made of magnetite. The high-frequency heating element according to any one of claims 2 to 6, wherein the elastomer includes silicon rubber or fluorine rubber. On a part of the surface on which the object to be heated of the object to be heated is not placed and a metal object to be heated on which the coating layer containing an organic polymer is placed. A cooking utensil for a high-frequency overheating device comprising the high-frequency heating element according to any one of claims 1 to 7. The cooking utensil for a high-frequency heating device according to claim 8, wherein an area of the high-frequency heating element provided on the metal heated object placing tray is 0.1 m ² or less. The cooking utensil for a high-frequency heating device according to claim 8 or 9, wherein the film thickness of the high-frequency heating element provided on the metal heated object mounting tray is 0.5 to 2 mm.

Images