COOKING APPLIANCE

The cooking appliance has a casing having an open front, a cooking space formed therein and an opening part formed at one side thereof, a microwave generator for generating and directing a microwave toward the cooking space; an induction coil facing the opening part, the cooking part being arranged outside the space; and a shielding plate arranged between the induction coil and the opening part. The shielding plate includes an insulator; a first pattern, which is formed on one surface of the insulator and faces the opening part, and a second pattern, which is formed on the other surface of the insulator and is perpendicular to the first pattern. The first pattern has a slit formed in a region facing the opening part.

TECHNICAL FIELD

The present invention relates to a cooking appliance, and more particularly, to a cooking appliance having an induction coil.

BACKGROUND ART

As a device for cooking food, etc. (hereinafter referred to as food), it can be classified into a closed type cooking device and an open type cooking device according to the shape of a space in which food is placed.

The closed type cooking device cooks food in a state in which a cooking space is shielded, such as ovens and microwave ovens,

The open type cooking device cooks food in an open space, such as a cooktop.

A microwave oven is a cooking device that uses microwaves to heat and cook food to be cooked using microwaves, molecules constituting food vibrate with microwaves, and as a result, the temperature of food rises due to frictional heat generated between the constituent molecules. do. This heating method is called dielectric heating method.

Recently, in addition to the heating method by microwaves, there is an induction heating and cooking combined microwave oven equipped with an induction coil as a separate heating means and capable of cooking food in a cavity by induction heating via the induction coil.

The microwave oven using induction heating and cooking requires a shielding structure that prevents microwaves from penetrating into the induction coil.

An example of a cooking appliance capable of protecting an induction coil by installing a shielding plate for shielding electromagnetic waves penetrating into an induction coil inside the cooking appliance is a microwave oven for both induction heating and cooking disclosed in Korean Registered Patent Publication No. 10-0176773 B1 (published on May 15, 1999).

The induction heating and cooking combined microwave oven comprises a working coil generating an induced current; and the shielding plate, the shielding plate comprises a first metal wire portion in which a plurality of metal wires are arranged parallel to each other, and a second metal wire portion in which a plurality of metal wires are arranged parallel to each other so as to be spaced apart from the first metal wire portion at a predetermined interval and face each other at a predetermined angle and the shielding plate comprises an insulating material interposed between the first metal wire portion and the second metal wire portion.

DISCLOSURE

Technical Problem

The shielding plate according to the prior art has a problem in that when the first metal wire portion contacts the casing, the first metal wire portion can become an eddy current passage of induction, and the shielding plate is heated and damaged. In addition, there is a problem in that the heating efficiency is lowered because the magnetic field does not pass through the shielding plate.

An object of the present invention is to provide a cooking appliance in which a shielding plate does not become an eddy current passage for induction and the heating efficiency of an induction coil is high.

Technical Solution

The cooking appliance according to the present embodiment comprises a casing having an open front, having a cooking space formed therein and having an opening formed at one side thereof; a microwave generator for generating a microwave toward the cooking space; an induction coil facing the opening, and arranged outside the casing for induction heating; and a shielding plate arranged between the induction coil and the opening. The shielding plate comprises an insulator; a first pattern formed on one surface of the insulator and facing an opening; and a second pattern formed on the other surface of the insulator and perpendicular to the first pattern.

One example of the first pattern has a slit formed in a region facing the opening.

Eddy current formation can be prevented by the slit, and the first pattern does not function as an eddy current path.

The shielding plate is larger than the opening, and a peripheral portion of the shielding plate contacts a periphery of the opening.

The first pattern comprises a plurality of metal wire lines parallel.

Each of the plurality of parallel metal wire lines respectively comprise an opening facing portion facing the opening; and a casing contact portion contacting the casing.

The slit is a formed in the opening facing portion.

The slit having a distance of 15 mm or less from a periphery of the opening.

The slit has a length of 0.5 mm or less.

A film or coating is formed disposed on the surface of the shielding plate on which the first pattern is formed, and the film or coating covers the first pattern.

The other example of the cooking appliance further a spacer made of an insulating material is disposed between the opening and the first pattern. The first pattern is spaced apart from a periphery of the opening by the spacer.

Since the first pattern is not in contact with the casing by the spacer, eddy current can be blocked, and leakage of electromagnetic waves between the shielding plate and periphery of the opening can be prevented by the spacer.

A size of the spacer is larger than the opening, and the spacer contacts periphery of the opening part.

A portion of the shielding plate overlaps the casing, and the shielding plate brings the spacer into close contact with periphery of the opening part.

The spacer is a coating layer coated on one surface of the shielding plate.

Advantageous Effect

According to an embodiment of the present invention, the first pattern does not function as an eddy current passage due to the slits formed in the first pattern, and eddy current is not generated when the induction coil is operated.

Since the spacer is disposed between the first pattern and periphery of the opening part so that the first pattern does not contact the casing, eddy currents can be blocked, and leakage of electromagnetic waves between the shielding plate and periphery of the opening part can be prevented.

BEST MODE

Hereinafter, specific embodiments of the present invention will be described in detail with drawings.

FIG.1is a perspective view showing the inside of a cooking appliance according to an embodiment of the present invention;FIG.2is a perspective view partially cut away along line II-II shown inFIG.1;FIG.3is a cross-sectional view showing an example of a cooking appliance according to an embodiment of the present invention;FIG.4is a top view of the shielding plate shown inFIG.2;FIG.5is a bottom view of the shielding plate shown inFIG.2.

The cooking appliance according to the present embodiment may comprise a casing10in which a cooking space S is formed. The casing10may have a three-dimensional shape.

The casing10comprises the lower wall12, a pair of side walls14and16disposed above the lower wall12, and the back wall18, and the lower wall12in an upward and downward direction. A spaced upper wall20may be comprised.

The front of the casing10may be open, and the cooking space S may be formed inside the casing10. An example of the material of the casing10, particularly the lower wall12, may be SUS403.

An opening13may be formed on one side of the casing10. The opening13may be formed in one of the lower wall12, the pair of side walls14and16, the back wall18, and the upper wall20.

The lower wall12may comprise a lower body21in which a hole21alarger than the opening13(seeFIG.3) is formed, and a forming body22forming the opening13.

The lower body21and the forming body22may be integrally formed, or may be formed as separate bodies and coupled to each other.

A forming space23may be formed inside the forming body22, and an opening13may be formed at a lower side of the forming space23. The opening13may be smaller in size than the forming space23.

A periphery24of the opening may be formed in the forming body22. The periphery24of the opening may protrude from the lower end of the inner wall forming the forming space23.

A glass26may be disposed in the forming space23to prevent foreign substances such as food from penetrating into the shielding plate40. The forming body22may be disposed to surround the outer circumference of the glass26. One example of glass26may be heat-resistant glass.

The glass26may be formed larger than the opening13. The glass26may be seated on a periphery24of the opening.

The glass26may be bonded to casing10using a sealant.

The cooking appliance may further comprise a microwave generator (30, seeFIG.1) generating microwaves into the cooking space (S). The cooking appliance may further comprise a heater32(seeFIG.1) for heating the cooking space S. A microwave generator30and a heater32may be disposed in the casing10.

An example of the microwave generator30may comprise a magnetron for generating electromagnetic waves, a waveguide for connecting the magnetron and the casing, and introducing electromagnetic waves into the cooking space S, and an agitator such as a stirrer fan rotating for uniform heating.

At least one heater32may be installed in the casing10.

The cooking appliance may further include an induction coil40(seeFIG.2) for induction heating, and a shielding plate50(seeFIGS.2and3) disposed between the induction coil40and the opening13.

The induction coil40is a 20-70 kHz band induction working coil located outside the cooking space S, so that the casing10is not heated, and the container containing the food located in the cooking space S can be heated.

The induction coil40may be spaced apart from the microwave generator30and the heater32. When the microwave generator30and the heater32are disposed above the casing10, the induction coil40may be disposed below the casing10.

The cooking appliance may further comprise a bracket42supporting the induction coil40.

The induction coil40may be disposed above the bracket42, and the induction coil40and the bracket42may constitute an induction module IM.

The induction coil40may be disposed outside the casing10toward the opening13. The size of the induction coil40may be smaller than the size of the opening13.

The bracket42may be larger than the opening13. The bracket42may be coupled to the lower wall12. The bracket42may comprise a fastening part43coupled to the lower wall12with a fastening member such as a screw.

A shielding plate holder44(seeFIG.3) made of non-metal and pressing the shielding plate50upward may be disposed on the bracket42.

The shielding plate holder44may be disposed between the bracket42and the shielding plate50, and is placed on the bottom of the shielding plate50so that the shielding plate50is in close contact with the lower surface of the lower wall12.

The shielding plate holder44may have a ring shape.

The shielding plate50is in close contact with the casing10from the outside of the cooking space S, and can block sparks caused by the discontinuous surface of the edges.

As shown inFIGS.3to5, the shielding plate50may include an insulator60, a first pattern70and a second pattern80.

The insulator60may insulate the first pattern70and the second pattern80between the first pattern70and the second pattern80.

Examples of the first pattern70and the second pattern80may be alumina-based and may be formed by an etching process.

The first pattern70and the second pattern80may be copper wires or non-magnetic stainless wires.

The first pattern70may be formed on one surface62of the insulator60. As shown inFIG.3, the first pattern70may face the opening13.

The second pattern80may be formed on the other surface64of the insulator60. The second pattern80may be spaced apart from the first pattern70and may be formed on a surface opposite to the surface of the insulator60on which the first pattern70is formed.

As shown inFIGS.4and5, the second pattern80may be perpendicular to the first pattern70. The first pattern70and the second pattern80may selectively shield electromagnetic waves. For example, in the electromagnetic wave generated by the microwave generator30, the horizontal polarization of the horizontal polarization and the vertical polarization is removed by the first pattern70, and the vertical polarization transmitted through the first pattern70is removed by the second pattern80. As another example, in the electromagnetic wave generated by the microwave generator30, the vertical polarization of the horizontal polarization and the vertical polarization is removed by the first pattern70, and the horizontal polarization transmitted through the first pattern70is removed by the second pattern80.

The shielding plate50may be horizontally disposed below the lower wall12. One surface62of the insulator60may be an upper surface of the insulator60, and the other surface64of the insulator60may be a lower surface of the insulator60.

The first pattern70may be an upper pattern or upper filter formed on the upper surface62of the insulator60, and the second pattern80may be a lower pattern or lower filter formed below the lower surface62of the insulator60.

As shown inFIG.4, the first pattern70may be composed of a plurality of metal wire lines72parallel to each other, hereinafter referred to as a plurality of first metal wire lines. The first pattern70may be composed of a combination of a plurality of first metal wire lines72.

As shown inFIG.5, the second pattern80may be composed of a plurality of metal wire lines82parallel to each other, and hereinafter referred to as a plurality of second metal wire lines. The second pattern80may be composed of a combination of a plurality of second metal wire lines82.

Each of the first metal line72and the second metal line82may be formed in a straight-line shape.

The first metal line72and the second metal line82may be formed in directions perpendicular to each other. For example, when the first metal wire line72is formed long in the left and right direction, the second metal wire line82may be formed long in the front and rear direction.

The shielding plate50can shield electromagnetic waves of 13.56 MHz, 27.12 MHz, 40.68 MHz, 433 MHz, 915 MHz, and 2450 MHz, which are frequencies of the microwave generator30, by the first metal line72and the second metal line82. and the magnetic field of 20 to 70 kHz, which is the frequency of the induction coil40, can be transmitted.

The shielding plate50may be formed larger than the opening13. The shielding plate50may block the opening13at a lower side of the opening13.

As shown inFIG.3, the shielding plate50may comprise a center portion CA toward the opening13in an upward direction, and a peripheral portion OA located around the center portion CA and surrounding the center portion CA.

The center portion CA of the shielding plate50may be an opening facing portion located below the opening13and facing the opening13in an upward direction.

The peripheral portion OA of the shielding plate50may be positioned below the periphery24of the opening and may face toward the periphery24of the opening in an upward direction.

The peripheral portion OA of the shielding plate50may contact the periphery24of the opening and may be a casing contact portion contacting the casing10.

The peripheral portion OA of the shielding plate50may overlap the periphery24of the opening by an overlap length L (seeFIG.3).

The first metal line72formed on the upper surface62of the shielding plate50may also comprise an opening facing portion CA and a periphery facing portion OA (casing contact portion), and a portion of the first metal line72may be the opening facing portion, and the rest may be the periphery facing portion.

In the first pattern70, a slit74may be formed in a region facing the opening13(i.e., an opening facing portion CA). The slit74may be formed in the first metal line72. The slit74may face the opening13without facing the periphery24of the opening.

If the slit74is not formed in the opening facing portion CA and the induction coil40is operated, the first metal line72of the first pattern70contacts the casing10and the first metal line72of the first pattern70may be heated due to the eddy current. That is, the heating efficiency of the vessel by the induction coil40may be low.

Since the first metal line72of the first pattern70is disconnected by the slit74, eddy current can be minimized and heating efficiency by the magnetic field of the induction coil40can be high.

The slit74may be located eccentrically in the first metal line72. The slit74may be proximate a periphery24of the opening. The slit74may be positioned at a distance of less than 15 mm from the periphery24of the opening and less than 15 mm from the periphery24of the opening.

As shown inFIG.4, the slits74may be formed in all of the first metal line lines72having the opening facing portion CA. The length of the slit74may be 0.5 mm or less in the length direction of the first metal wire line72. The first metal line72is disconnected by the slit74, and an eddy current passage through the first metal line72can be blocked.

The first metal wire line72may be a metal wire line cut by the slit74.

An example of the first metal wire line72may be that the width of the adjacent first metal wire line72is 3 mm, the interval between the first metal wire lines72is 0.5 mm, and the slit74is 0.1 mm.

All of the second metal wire lines82formed on the lower surface64of the shielding plate50may not contact the casing10and may be a spaced portion spaced apart from the casing10.

As shown inFIG.5, the second metal wire line78is spaced apart from the casing10, so a separate slit74does not need to be formed.

As described above, the slit74is formed in the first metal line72in contact with the periphery24of the opening, and the second metal line82is formed to be spaced apart from each of the first metal line72and the casing10, eddy current may not be generated when the induction coil40operates.

FIG.6is a modified example of the shielding plate shown inFIG.3.

As shown inFIG.6, the shielding plate50may have a film90or a coating covering the first pattern70is disposed on the surface62on which the first pattern70is formed. A film92or coating covering the second pattern80may be disposed on the surface62on which the second pattern80is formed.

The films90and92or the coating may protect the first pattern70and the second pattern80.

Since the first pattern70and the second pattern80can be oxidized as the temperature rises, the insulator60has the films90and92or plating covering the first pattern70and the second pattern80may be formed.

The films90and92may be resin films suitable for oxidation prevention.

FIG.7is a cross-sectional view showing another example of a cooking appliance according to an embodiment of the present invention;FIG.8is a top view of the shielding plate shown inFIG.7;FIG.9is a bottom view of the shielding plate shown inFIG.7.

As shown inFIG.7, the cooking appliance may comprise a casing10, a microwave generator30, an induction coil40, and a shielding plate50, and may further include a spacer100.

The casing10may have a front surface open, a cooking space S may be formed therein, and an opening13may be formed at one side. Since the casing10is the same as or similar to the casing of one example of the cooking appliance, the same reference numeral is used, and a description thereof is omitted to avoid redundant description.

Since the microwave generator30can generate microwaves into the cooking space and is the same as or similar to the microwave generator30of an example of a cooking appliance, the same reference numerals are used, and description thereof is omitted to avoid redundant description.

The induction coil40faces the opening13and is disposed outside the casing to perform induction heating. Since the induction coil40is the same as or similar to the induction coil40of one example of a cooking appliance, the same reference numerals are used and duplicate descriptions are given. To avoid this, the description is omitted.

The shielding plate50′ is disposed between the induction coil40and the opening13, and may be spaced apart from the casing10by the spacer100.

The shielding plate50′ is similar to the shielding plate50of an example of a cooking appliance in configuration other than the first pattern70′, and a description thereof is omitted to avoid redundant description.

A portion of the shielding plate50′ may overlap the casing10. The shielding plate50′ may adhere the spacer100to the periphery24of the opening.

The shielding plate50′ may comprise an insulator60, a first pattern70′, and a second pattern80.

The configuration of the insulator60may be similar to that of the insulator60of an example of a cooking appliance, and a detailed description thereof will be omitted to avoid redundant description.

The first pattern70′ may be formed on one surface of the insulator60and face the opening13. The first pattern70′ may be spaced apart from the periphery24of the opening13by the spacer100. The first pattern70′ is spaced apart from the casing10at a predetermined interval, so that eddy currents can be blocked.

The first pattern70′ is electrically spaced apart from the periphery24of the opening, and a slit74, like an example of a cooking appliance, may not need in the first metal line72constituting the first pattern70′.

The second pattern80is formed on the other surface of the insulator60, may be perpendicular to the first pattern70′, may be similar to the second pattern80of an example of a cooking appliance, and avoid redundant description. For this reason, a detailed description thereof will be omitted to avoid redundant description.

The spacer100may be disposed between the opening13and the first pattern70′, and may be made of an insulating material.

The size of the spacer100may be larger than the size of the opening13. The spacer100may contact the periphery24of the opening. The spacer100may have a central portion facing the opening13and a peripheral portion overlapping the periphery24of the opening in the vertical direction.

The spacer100is interposed between the periphery24the opening and the shielding plate50′ to shield microwaves between the periphery24of opening and the shielding plate50′, and to prevent leakage of the microwaves. The spacer100may prevent shielding of microwaves between the glass26and the shielding plate50′.

The spacer100may have a maximum thickness of 0.2 mm or less and a minimum thickness of 0.01 mm.

An example of the spacer100may be an insulating material made of glass fibers or the like.

The spacer100is not limited to a member separate from the shielding plate50′, and may be a coating layer coated on one surface62of the shielding plate50′.

The above description is merely illustrative of the technical spirit of the present disclosure, and various modifications and changes can be made by those of ordinary skill in the art, without departing from the scope of the present disclosure.

Therefore, the embodiments disclosed in the present disclosure are not intended to limit the technical spirit of the present disclosure, but are intended to explain the technical spirit of the present disclosure. The scope of the technical spirit of the present disclosure is not limited by these embodiments.

The scope of the present disclosure should be interpreted by the appended claims, and all technical ideas within the scope equivalent thereto should be construed as falling within the scope of the present disclosure.