JP3155497B2 - Cooking device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooking apparatus for cooking an object to be heated such as food stored in a heating chamber.

[0002]

2. Description of the Related Art As a heating cooking apparatus for heating and cooking food stored in a heating chamber, a heating apparatus based on dielectric heating using electromagnetic waves such as a magnetron, a radiant heating apparatus using hot air or the like, or a combination thereof is used. Those used have been developed. Further, there is also known a device in which the above-mentioned heating is performed while supplying steam into the heating chamber (for example, Japanese Patent Publication No. 59-22132, Japanese Patent Laid-Open No.
-49854, JP-A-9-4849).

FIG. 8 is a configuration diagram of a steam oven which is a conventional heating cooking device using hot air. A tray 42 for placing an object to be heated is provided inside the heating chamber 41, and a pot-shaped recess 43 for accommodating a heating unit is formed on the inner wall of the heating chamber 41. A motor rotation shaft 45 of a fan motor 44 installed behind the recess 43 penetrates a rear wall of the recess 43, and a fan 46 is fixed to a tip end thereof. A sheathed wire heater 47 is provided around the fan 46 around the fan 46, and is heated by being supplied with electric power from a circuit (not shown). The fan 46 has a structure in which air is sucked in from the front on the inner peripheral side and sent out to the outer peripheral side. The sent out air comes into contact with the heater 47 and is heated to return into the heating chamber 41.

[0004] A steam generator 48 is attached to the heating chamber 41, and supplies electric power to the heater 481 to supply water to the water tank 482.
The water vapor obtained by heating and evaporating the water inside is supplied to the heating chamber 41. Steam is effective not only to prevent the food surface from drying during heating by hot air, but also to improve the heating efficiency. That is, when heating is performed while adding steam (especially overheated steam), a larger amount of heat can be given to the food from the steam that has come into contact with the food, so that the cooking time can be reduced as compared with the case where steam is not added. it can.

In the cooking device having the above-described structure, the sheathed wire heater 47 has a surface covered with a heat-resistant insulator, and it is difficult to widen the surface area structurally. Low. For this reason, if an excessive amount of electric power is supplied to the heater, the inside of the heater temporarily becomes excessively high temperature, which may cause breakage of the heating wire or the like. We had to limit the maximum power.

In view of such a problem, the present inventors have proposed a heating cooking apparatus having a novel configuration in Japanese Patent Application No. 9-82139. That is, this heating cooking device has a heating chamber for accommodating an object to be heated, a substantially cylindrical bowl-shaped recess made of an insulator attached to the back of the heating chamber,
A fan provided in the recess, for sending air sucked from the center front to the outer peripheral side, a cylindrical heating element disposed around the outer periphery of the fan inside the concave, and wound around the outer periphery of the concave. And a power supply means for supplying high-frequency power to the coil and inductively heating the heating element.

In this heating cooking device, the heating element and the coil can be arranged very close to each other with the peripheral wall of the recess therebetween, so that more magnetic flux induced by the coil passes through the internal opening of the heating element. . In addition, an induced current flows through the heating element mainly in the circumferential direction. For this reason, the heating efficiency is good, and the food can be quickly cooked without spoiling the taste.

[0008]

In order to obtain high heating performance in this heating cooking apparatus, for example, a larger heating power may be supplied to the coil, but there are various restrictions such as cost and size. Therefore, one of the major issues is how to use the amount of heat generated by the heating element for heating without waste.

The present invention has been made in view of the above points, and is an improvement of the above-mentioned novel heating cooking apparatus. It is an object of the present invention to provide a heating cooking apparatus capable of performing more efficient heating. It is in.

[0010]

Means for Solving the Problems, Embodiments of the Invention, and Effects of the Invention The heating and cooking apparatus of the present invention made to solve the above-mentioned problems includes: a) a heating chamber for accommodating an object to be heated; b) a recess formed of a substantially cylindrical insulator having one end face communicating with the heating chamber and the other end face substantially closed; c) a recess provided in the recess toward the heating chamber, from the front of the center. Blower means including a fan for sending the sucked air to the outer peripheral side; d) surrounding the outer periphery of the fan, and having a predetermined gap with the peripheral wall so that air can flow along the peripheral wall of the recess. A heating device comprising: a substantially cylindrical metal body provided; a coil wound around an outer peripheral side of a peripheral wall of the recess; and a power supply unit for supplying high-frequency power to the coil and inductively heating the metal body. And means.

In the heating and cooking apparatus according to the present invention, when the power supply means supplies high frequency power to the coil, an alternating magnetic flux passing through the inner opening of the metal body is generated in the coil. This magnetic flux induces an alternating current in the metal body in the circumferential direction, and the metal body itself is induction-heated. The blowing means sucks air in the heating chamber and sends it out to the heated metal body. Since the metal body is provided with a predetermined gap from the peripheral wall of the recess, air passes not only on the inner peripheral side of the metal body but also on the outer peripheral side (that is, the gap between the peripheral wall of the recess and the metal body). . Since the coil exists on the outer peripheral side of the metal body, the metal body generates more heat on the outer peripheral side than on the inner peripheral side. Therefore, the heat exchange is effectively performed by the air passing through the outer peripheral side of the metal body, and the temperature becomes sufficiently high to return to the heating chamber.

As described above, according to the cooking device of the present invention, the heat exchange efficiency between the metal body and the air is remarkably improved, so that the temperature inside the heating chamber rises quickly. For this reason, while heating cooking can be completed in a short time, good-tasting cooking can be performed.

Further, the metal body has irregularities in the circumferential direction, the projections abut on the inner surface of the peripheral wall of the recess, and a gap is formed between the peripheral wall and the concave part of the metal body. Is preferred.

According to this structure, the concave portion of the metal body is stably supported with an appropriate gap from the peripheral wall of the concave portion, and the gap formed between the concave portion of the metal body and the peripheral wall of the concave portion. The air can be circulated. In addition, in the heating cooking device of the present invention, heat is generated by resistance loss of current flowing in the metal body in the circumferential direction. Therefore, when the metal body is configured as described above, the distance in the circumferential direction is increased, the resistance is increased, and the metal body is increased by a smaller high frequency current. Heating power can be obtained. Further, since the effective surface area of the metal body is increased, the efficiency of heat exchange with the surrounding air is further improved.

Further, for example, it is more preferable that the metal body has a wavy shape in which peaks and valleys extend in the direction of the air flow generated by the fan.

According to this configuration, the air flow generated by the fan flows along the peaks and valleys of the wave of the metal body, and heat exchange is achieved therebetween. That is, since the metal body does not hinder the smooth flow of air, a sufficient air volume or pressure can be obtained. Thereby, the circulation of the air between the inside of the heating chamber and the recess can be performed well, and the hot air can be spread to every corner of the heating chamber with a large air volume.

Further, if the metal body has a structure in which the gap between the peripheral wall of the recess and the peripheral wall of the recess is wider on the rear side than on the front side, more air flows through the gap between the outer peripheral surface of the metal body and the peripheral wall of the recess. Easier to do.

Further, it is preferable that the metal member is divided into a plurality of members in the direction of the rotation axis of the fan, and the metal members are separated from each other at predetermined intervals. According to this configuration, the air flows from the inner peripheral side to the outer peripheral side of the metal body through the gap between the plurality of separated metal bodies, so that a large amount of air also flows to the outer peripheral side of the metal body.

Further, in the heating and cooking apparatus of the present invention, the magnetic flux is coarse on both end sides of the substantially cylindrical coil wound along the outer peripheral wall of the recess, and the magnetic flux is dense on the center side. For this reason, more current is induced in the metal body located inside the center of the coil, and the amount of heat generated also increases. That is, the amount of heat generated by the metal body becomes uneven in the direction of the rotation axis of the fan. When such non-uniformity occurs, for example, the metal body must be made of a material that can withstand the temperature of the hottest part, and there is a high possibility that the choice of the material is narrowed and the cost is increased.

Therefore, the metal member is divided into three or more members in the direction of the rotation axis of the fan, and the metal member disposed at the center thereof has a different thickness in the radial direction from the two metal members disposed at both ends. It is good to have composition which has.

When an induced current flows through the metal body due to the magnetic flux generated in the coil, the metal body has an inductance impedance. Since this impedance changes depending on the thickness of the metal body, the power consumed when a high-frequency magnetic field of a certain frequency is applied to the metal body depends on the thickness of the metal body,
At a certain wall thickness, the power is at a maximum, and power is reduced whether it is thinner or thicker. In addition, since the impedance characteristic changes depending on the material of the metal body, the wall thickness giving the maximum power also changes. Therefore, by setting the thickness of the metal body disposed on the center side to an appropriate value that is thinner or thicker than the thickness of the two metal bodies on both sides, the metal body on the center side is given the same amount of magnetic flux. The amount of heat generated can be made smaller than the others.In fact, the magnetic flux becomes dense at the center side, but the magnetic flux becomes coarse at both ends, so the heat generated at each metal body can be almost equalized. it can.

Further, the metal member is divided into three or more members in the direction of the rotation axis of the fan, and the metal member disposed on the center side thereof is closer to the peripheral wall of the recess than the two metal members disposed at both ends. May be configured to have a wide gap.

That is, the farther the metal body is away from the peripheral wall of the recess, the longer the distance from the coil and the lower the magnetic flux density. Therefore, according to this configuration, the induced current flowing through the metal members arranged at the center is reduced, and as a result, the amount of heat generated in each metal member can be substantially equalized.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a heating and cooking apparatus according to the present invention will be described below with reference to FIGS. FIG. 1 is a configuration diagram showing a schematic side cross section of a main part of the heating and cooking apparatus of the present embodiment, FIG. 2 is a plan view (a) and a partial side cross sectional view (b) showing the appearance of a heating element in FIG. FIG. 3 is a detailed enlarged view of a portion A in FIG.

As shown in FIG. 1, the front opening of a box-shaped heating chamber 1 can be substantially closed by a door 2.
A heating unit 10 is provided at the rear of the device. The heating unit 10 includes a heating unit using electromagnetic induction heating and the heating chamber 1.
And air blowing means for circulating air through the air.

The heating means includes a case 11 made of a substantially cylindrical insulator fixed to the rear wall 1a of the heating chamber 1, and a heating means 2 provided at a predetermined position inside the case 11 as shown in FIG.
Heating elements 121 and 122 each having a substantially cylindrical shape and the case 11
And a high frequency power supply unit 14 including an inverter control circuit for supplying high frequency power to the coil 13.

On the other hand, the blower means comprises a fan motor 15 arranged behind the case 11 and a fan 17 attached to the tip of a rotating shaft 16 penetrating the center of the rear wall of the case 11. The fan 17 has a structure in which air sucked from the front center is sent to the outer peripheral side of the wing body.
7, an intake hole 3 is provided on the inner peripheral side, and an outlet hole 4 is provided on the outer peripheral side.

As shown in FIG. 2, the heating elements 121 and 122
Is formed by molding a metal plate material such as stainless steel whose cross section is processed into a corrugated shape into a substantially cylindrical shape. When this is inserted into the inside of the cylindrical case 11, the tip of the corrugated crest that protrudes outward has a case shape. 11 is held in contact with the inner surface of the peripheral wall. Since the peripheral wall of the case 11 has a moderately gentle inclination, the two heating elements 12 are formed by slightly differentiating the inner diameters of the heating elements 121 and 122.
1 and 122 can be arranged in the case 11 while keeping an appropriate interval.

In the above configuration, when a high-frequency current is supplied from the high-frequency power supply section 14 to the coil 13, the heating element 12
Magnetic flux passing through the central openings of the heating elements 121 and 122 is generated, and the magnetic flux causes an induced current to flow in the circling direction of the heating elements 121 and 122. Joule heat is generated by this induced current, and the heating elements 121 and 122 themselves are heated. Of course, a part of the magnetic flux penetrates the heating elements 121 and 122 vertically or obliquely, thereby locally generating an eddy current. However, the entire heating value is dominated by the current circulating around the heating elements 121 and 122. It is a target.

When the fan 17 is driven to rotate by the fan motor 15 (rotational speed is, for example, about 2700 rpm), the air sucked into the case 11 from the heating chamber 1 through the intake hole 3 is sent to the outer peripheral side of the fan 17. And passes through the inner peripheral sides of the heating elements 121 and 122 and
21 and also from the gap between the heating elements 121 and 122, it goes around the outer circumference of the heating elements 121 and 122, and passes through the gap between the peripheral wall of the case 11 and the heating elements 121 and 122. For this reason, the air flow removes heat from both surfaces of the heating elements 121 and 122 and becomes heated air. This hot air is blown out from the blowing hole 4 into the heating chamber 1, and as shown by an arrow in FIG.
The air is drawn again into the case 11 from the intake hole 3 around the inside. By circulating air between the inside of the heating chamber 1 and the inside of the case 11, the temperature inside the heating chamber 1 rises, and the food contained in the heating chamber 1 is heated and cooked.

Heating elements 121 and 122 in the above embodiment
Uses a metal plate having a corrugated cross section, but it may be formed by molding a flat metal plate into a cylindrical shape having a predetermined gap with the peripheral wall of the case 11. However, according to the heating elements 121 and 122 having the above configuration, the heating elements 12
Air is not only circulated on the outer peripheral side of 1, 122 but also the contact area with the surrounding air is increased, which is advantageous in terms of heat exchange efficiency. In addition, since the distance in the circling direction is increased, the electric resistance is increased, and a large heating power can be obtained with a smaller high-frequency current. Further, even when the metal plate expands during heating, the interval between adjacent peaks or valleys is reduced to absorb the expansion, so that an excessive force can be prevented from being applied to the peripheral wall of the case 11.

FIG. 4 is a detailed enlarged view showing another embodiment of the heating elements 121 and 122. In this embodiment, the heating chamber 1
Heating elements 121, 1 so that the central opening facing
22 are configured. For this reason, since the gap between the heating elements 121 and 122 and the peripheral wall of the case 11 is larger on the rear side of the fan 17, the airflow generated by the fan 17 is more smoothly provided on the outer peripheral side of the heating elements 121 and 122. Distribute.

FIG. 5 is an external view showing another embodiment of the heating elements 121 and 122. As shown in FIG. In this embodiment, the heating elements 121 and 122 are formed of a metal plate having a corrugated cross section as in the example of FIG. 2, but the peaks and valleys of the waves extend along the direction of the air flow by the fan 17. Is formed.
For this reason, since the heating elements 121 and 122 have a rectifying action of the air, the flow of the air generated by the fan 17 becomes smooth and the blowing efficiency is improved. For this reason, the heat generated by the heating elements 121 and 122 does not stay in the case 11, and the inside of the heating chamber 1 is heated more efficiently.

In the heating cooking apparatus having the structure shown in FIG. 3, since the magnetic flux becomes denser near the center of the cylindrically wound coil 13 than at both ends, it is located inside the vicinity of the center of the coil 13. A large amount of circulating current is induced in the heating elements 121 and 122. Therefore, the heating elements 121 and 122 are unevenly heated in the direction of the rotation shaft 16. In the presence of such non-uniformity of heating, for example, only a certain portion of the heating element becomes extremely hot, so that it is necessary to use a metal having characteristics capable of withstanding the temperature.

To solve such a problem, the configuration shown in FIG. 6 or FIG. 7 can be adopted. That is, in the example shown in FIG. 6, the heating elements 121, 122, and 123 divided into three in the direction of the rotating shaft 16 are separately arranged at predetermined intervals. The second heating element 1 located at the center
Reference numeral 22 denotes first and third heating elements 121 and 12 located on both sides.
It has an inner diameter smaller than 3. Since the second heating element 123 is farther from the coil 13 than the other heating elements 121 and 122, the magnetic flux passing through the inner opening is reduced despite being arranged at the center. Therefore, the current induced in the second heating element 122 is reduced, and as a result, the amount of heat generated in the first to third heating elements 121 to 123 can be substantially equalized.

In the example shown in FIG. 7, the heat generating elements 121, 122, and 123 divided into three in the direction of the rotation shaft 16 are separately arranged at predetermined intervals, and the second heat generating element 122 is provided.
First located on both sides of the Waso, third heating element 121, 123
The thickness of the metal plate is made thinner than that. Generally, when an induced current flows through the heating elements 121 to 123 by the magnetic flux as described above, the heating elements 121 to 123 each have an impedance of inductance. Since this impedance varies depending on the thickness of the heating element, the power consumed when a high-frequency magnetic field of a certain frequency is applied to the heating element depends on its thickness. The power is reduced whether the wall thickness is thinner or thicker. In addition, since the impedance characteristic varies depending on the material of the heating element, the thickness at which the maximum power is applied also depends on the material.

Therefore, the thickness of the second heating element 122 is made larger than the thickness of the first and third heating elements 121 and 123 in consideration of the materials of the heating elements 121 to 123 and the frequency of the high-frequency current flowing through the coil 13. Determine the appropriate value for thin or thick. Accordingly, the amount of heat per unit volume generated by the second heating element 122 with respect to the same amount of magnetic flux is equal to the first and third heating elements 121, 1
23, which is relatively smaller. Actually, the coil 13
The magnetic flux is dense on the center side and coarse on both ends, so that the amount of heat per unit volume generated by the first to third heating elements 121 to 123 is almost equalized, and Uniformity is reduced.

The above embodiment is merely an example, and it is apparent that changes and modifications can be made as appropriate within the scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a schematic side sectional view of a main part of a heating cooking device according to an embodiment of the present invention.

FIG. 2A is a plan view illustrating the appearance of a heating element according to the present embodiment.
And a partial side sectional view (b).

FIG. 3 is a detailed enlarged view of a portion A in FIG. 1;

FIG. 4 is a detailed enlarged view showing a configuration of a heating element according to another embodiment.

FIG. 5 is an external view of a heating element according to another embodiment.

FIG. 6 is a detailed enlarged view showing a configuration of a heating element according to another embodiment.

FIG. 7 is a detailed enlarged view showing a configuration of a heating element according to another embodiment.

FIG. 8 is a configuration diagram of a conventional heating cooking device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Heating room 1a ... Rear wall 3 ... Inlet hole 4 ... Outlet hole 10 ... Heating unit 11 ... Cases 121, 122, 123 ... Heating element 13 ... Coil 14 ... High frequency power supply unit 15 ... Fan motor 16 ... Rotating shaft 17 ... Fan

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F24C 7/00 F24C 1/00 360 F24C 1/00 370 H05B 6/12 F24C 1/00 310

Claims (7)

(57) [Claims] A) a heating chamber for accommodating an object to be heated; b) a recess made of a substantially cylindrical insulator whose one end face communicates with the heating chamber and the other end face is substantially closed; A) a fan provided in the recess toward the heating chamber and including a fan for sending air sucked from the front of the center to an outer peripheral side; d) air surrounding the fan and enclosing the peripheral wall of the recess along the peripheral wall of the concave. A metal body having a substantially cylindrical shape disposed with a predetermined gap from the peripheral wall so that the peripheral wall can flow, a coil wound around the outer peripheral side of the peripheral wall of the recess, and high-frequency power supplied to the coil. Heating means comprising: a power supply means for supplying and inductively heating the metal body by heating. 2. The semiconductor device according to claim 1, wherein the metal body has irregularities in a circumferential direction, the convex portion abuts on an inner surface of a peripheral wall of the concave portion, and a gap is formed between the peripheral wall and the concave portion. The heating cooking device according to claim 1, wherein 3. The heating device according to claim 2, wherein the metal body has a wave shape in which peaks and valleys extend along the direction of the air flow generated by the fan. Cooking equipment. 4. The heating cooking according to claim 1, wherein the metal body has a configuration in which a gap between the recess and the peripheral wall is wider on a rear side than on a front side. apparatus. 5. The structure according to claim 1, wherein the metal body is divided into a plurality of parts in the direction of the rotation axis of the fan, and the metal bodies are separated from each other with a predetermined interval therebetween. Cooking device. 6. The metal member is divided into three or more members in the direction of the rotation axis of the fan, and the metal member disposed at the center thereof has a different thickness in the radial direction from the two metal members disposed at both ends. The heating and cooking apparatus according to claim 5, wherein the heating and cooking apparatus has a configuration. 7. The metal body is divided into three or more in the direction of the rotation axis of the fan, and the metal body disposed at the center thereof is closer to the peripheral wall of the recess than the two metal bodies disposed at both ends. 6. The heating cooking device according to claim 5, wherein the gap is wide.