Cooking appliance

Abstract

The present invention relates to a cooking appliance comprising: an outer heat insulation material disposed outside a heat insulation material in which a heating coil is accommodated; and a reflector disposed in an inner accommodation space of the heat insulation material to reflect radiant heat generated by the heating coil toward a top plate, whereby the heating efficiency and power efficiency of the heating coil can be improved.

Description

Cooking appliances

[0001] The present invention relates to a cooking appliance, and more particularly, to a cooking appliance capable of improving the heat generation efficiency and power efficiency of a heating coil by arranging an external insulation material on an outer surface of the insulation material that accommodates a heating coil and arranging a reflector that reflects radiant heat generated from the heating coil toward a top plate in an internal accommodation space of the insulation material.

[0002]

[0003] A cooking appliance is a type of home appliance for cooking food. It is installed in the kitchen and cooks food according to the user's intention.

[0004] These cooking appliances can be classified into various categories according to the heat source or type of fuel used.

[0005] Among these cooking appliances, a cooktop is used, which heats the food being cooked by placing it on top of a heat source placed underneath.

[0006] Depending on the type of heat source, cooktops can be classified into gas type heaters using gas combustion, radiant type heaters using electric heater heat generation, and induction type heaters using induction heating.

[0007] In particular, radiant type heaters and induction type heaters are preferred by users because they have a structure that prevents direct exposure to the heat source, have a superior appearance compared to gas type heaters, and do not generate combustion gases.

[0008] In this regard, U.S. Patent Publication No. 11,536,460 (Prior Document 001) discloses a cooking appliance having a radiant type heater.

[0009] The heater of the cooking appliance disclosed in prior art document 001 includes a heating coil provided as a resistance heating element and a container-shaped insulating material that accommodates the heating coil, and the heat generated from the heating coil is transferred to the top plate and then to the container, thereby enabling cooking of food stored in the container.

[0010]

[0011] The heater of the cooking appliance disclosed in the aforementioned prior art document 001 is configured to prevent heat generated from the heating coil from being transferred to the remaining portion except for the top plate using only a container-shaped insulating material.

[0012] Accordingly, in the heater of the cooking appliance disclosed in prior art document 001, a significant amount of the heat generated from the heating coil is transferred to the insulating material through conduction and radiation, and is released into the internal space of the cooktop through the outer surface of the insulating material.

[0013] Therefore, the heater of the cooking appliance disclosed in prior art document 001 has a problem in that the amount of heat generated from the heating coil and released into the interior space of the cooktop through the outer surface of the insulation is not transferred to the top plate and the container, resulting in power loss, and thus the heating efficiency and power efficiency of the heating coil may be significantly reduced.

[0014] The present invention has been devised to solve the problems of the prior art, and its first purpose is to provide a cooking appliance capable of improving the heat generation efficiency and power efficiency of a heating coil by configuring an external insulation material to be placed on the outer surface of the insulation material that accommodates the heating coil.

[0015] In addition, the present invention has a second object to provide a cooking appliance capable of further improving the heat generation efficiency and power efficiency of a heating coil by configuring a reflector that reflects radiant heat generated from a heating coil toward a top plate to be placed in an internal receiving space of an insulating material.

[0016] The objectives of the present invention are not limited to those mentioned above. Other objectives and advantages of the present invention not mentioned above can be understood through the following description and will be more clearly understood through the embodiments of the present invention. Furthermore, it will be readily apparent that the objectives and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0017]

[0018] A cooking appliance according to the present invention comprises: a heating unit; and a top plate that shields the heating unit from the upper side and on which a container for cooking is placed; wherein the heating unit comprises: a heating coil that generates heat by electric resistance; an insulating material that accommodates the heating coil therein; a case that is coupled to an outer surface of the insulating material; and a heat efficiency improving part that is arranged inside the insulating material or outside the case and improves the heat generation efficiency of the heating coil.

[0019] In addition, the thermal efficiency improvement unit may include a first external insulation material that is coupled to the outside of the bottom surface of the case and covers the bottom surface of the case.

[0020] Additionally, the heating unit may further include a first holder that fixes the first external insulation material to the bottom surface of the case.

[0021] In addition, the first holder may be provided with a first through hole formed through the bottom surface of the case, and the bottom surface of the case may be provided with a fastening hole formed through the bottom surface at a position corresponding to the first through hole.

[0022] Additionally, the first external insulation material may have a lower heat resistance temperature than the insulation material.

[0023] In addition, the thermal efficiency improvement unit may include a second external insulating material that is coupled to the outside of the cylindrical surface of the case and covers the cylindrical surface of the case.

[0024] In addition, the heating unit may further include a second holder that fixes the second external insulation material to the cylindrical surface of the case.

[0025] In addition, the second holder may have a connecting tab formed by bending toward the bottom surface of the case, and the connecting tab may have a second through hole formed penetrating toward the bottom surface of the case, and the bottom surface of the case may have a fastening hole formed penetrating in the vertical direction at a position corresponding to the second through hole.

[0026] Additionally, the second external insulation material may have a lower heat resistance temperature than the insulation material.

[0027] In addition, the thermal efficiency improvement unit includes a first external insulation material that is coupled to the outside of the bottom surface of the case and covers the bottom surface of the case; and a second external insulation material that is coupled to the outside of the cylindrical surface of the case and covers the cylindrical surface of the case; and the first external insulation material and the second external insulation material can be formed integrally.

[0028] In addition, the heat efficiency improvement unit may include a reflector that is provided inside the insulation material, is placed between the inner surface of the insulation material and the heating coil, and reflects heat generated from the heating coil toward the top plate.

[0029] In addition, the reflector has an inner surface arranged toward the heating coil and an outer surface arranged toward the inner surface of the insulating material, and the inner surface of the reflector may have a higher reflectivity than the outer surface of the reflector.

[0030] Additionally, the inner surface of the reflector can be surface-processed to have a higher reflectivity than the outer surface of the reflector.

[0031] Additionally, the inner surface of the reflector may be coated with a material having a higher reflectivity than the outer surface of the reflector.

[0032] In addition, the reflector has an inner surface arranged toward the heating coil and an outer surface arranged toward the inner surface of the insulating material, and the outer surface of the reflector can be arranged to be in contact with the inner surface of the insulating material.

[0033] Additionally, the inner surface of the reflector may be a vertical surface arranged parallel to the inner surface of the insulating material.

[0034] Additionally, the inner surface of the reflector may be an inclined surface inclined toward the top plate.

[0035] Additionally, the inner surface of the reflector may be a curved surface that is formed concavely toward the top plate.

[0036] In addition, the reflector has an inner surface arranged toward the heating coil and an outer surface arranged toward the inner surface of the insulating material, and a separation space can be formed between the outer surface of the reflector and the inner surface of the insulating material.

[0037] Additionally, the outer surface of the reflector may be provided with a protrusion formed to protrude toward the inner surface of the insulating material.

[0038]

[0039] The cooking appliance according to the present invention has the effect of improving the heat generation efficiency and power efficiency of the heating coil by configuring an external insulation material to be placed on the outer surface of the insulation material that accommodates the heating coil.

[0040] In addition, the cooking appliance according to the present invention has the effect of further improving the heat generation efficiency and power efficiency of the heating coil by arranging a reflector that reflects radiant heat generated from the heating coil toward the top plate in the internal receiving space of the insulation material.

[0041] In addition, the cooking appliance according to the present invention has the effect of minimizing design changes and minimizing increases in manufacturing costs by configuring the external insulation and reflector to be attached and fixed to the insulation while minimizing structural changes to the insulation and case constituting the heater.

[0042] In addition to the effects described above, specific effects of the present invention are described below while explaining specific details for carrying out the invention.

[0043]

[0044] Figure 1 is a front perspective view of a cooking appliance according to one embodiment of the present invention.

[0045] Figure 2 is an exploded perspective view of the cooktop illustrated in Figure 1.

[0046] Figures 3 and 4 are perspective views and bottom views of the heating unit constituting the cooktop illustrated in Figure 2.

[0047] Fig. 5 is an exploded perspective view of the heating unit illustrated in Fig. 3.

[0048] FIG. 6 is a bottom perspective view illustrating a state in which a first external insulation material is attached to the bottom surface of the case of the heating unit according to the first embodiment of the present invention.

[0049] Figure 7 is an exploded perspective view of Figure 6.

[0050] FIG. 8 and FIG. 9 are a top perspective view and a bottom perspective view showing a state in which a second external insulation material is attached to the outer surface of the case of the heating unit according to the second embodiment of the present invention.

[0051] Figure 10 is an exploded perspective view of Figure 9.

[0052] FIG. 11 is an exploded perspective view illustrating a configuration in which a first external insulation material and a second external insulation material are integrated and attached to a case of a heating unit according to a third embodiment of the present invention.

[0053] Fig. 12 is a top perspective view illustrating a configuration in which a reflector is placed inside an insulating material of a heating unit according to a fourth embodiment of the present invention.

[0054] Figure 13 is an exploded perspective view of Figure 12.

[0055] Figure 14 is a partially enlarged view of the reflector shown in Figure 13.

[0056] Fig. 15 is an exploded perspective view illustrating a configuration in which a lower fixing part is added to the reflector illustrated in Fig. 13.

[0057] Figures 16 to 19 are cross-sectional views of the vertical direction of the heating unit illustrated in Figure 12, showing configurations in which reflectors having different cross-sectional shapes are provided.

[0058]

[0059] The above-described objects, features, and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily practice the technical idea of ​​the present invention. In describing the present invention, if it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0060] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0061] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0062] Hereinafter, the phrase "any configuration is placed on (or below)" a component or "on (or below)" a component may mean that any configuration is placed in contact with the upper surface (or lower surface) of said component, and that other configurations may be interposed between said component and any configuration placed on (or below) said component.

[0063] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component.

[0064] As used herein, singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "consisting of" or "comprising" should not necessarily be construed to include all of the components or steps described in the specification, and should be construed to mean that some of the components or steps may not be included, or that additional components or steps may be included.

[0065] Additionally, the singular expressions used herein include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "consist of" or "comprises" should not be construed to necessarily include all of the various components or various steps described in the specification, and should be construed to mean that some of the components or some of the steps may not be included, or that additional components or steps may be included.

[0066] Throughout the specification, when we refer to "A and / or B", this means A, B, or A and B, unless otherwise stated, and when we refer to "C through D", this means C or more and D or less, unless otherwise stated.

[0067] Hereinafter, the present invention will be described with reference to drawings showing a configuration according to an embodiment of the present invention.

[0068] [Overall structure of the cooking appliance]

[0069] Hereinafter, the overall structure of a cooking appliance (1) according to an embodiment of the present invention will be described in detail with reference to the attached drawings.

[0070] FIG. 1 shows a front view of a cooking appliance (1) according to one embodiment of the present invention.

[0071] Referring to FIG. 1, a cooking appliance (1) according to one embodiment of the present invention may include a cooktop (20) and an oven section (10).

[0072] As shown, the cooktop (20) can be placed on the upper side of the oven section (10), and the oven section (10) can form the lower part of the cooking appliance (1).

[0073] Of course, the cooktop (20) and oven section (10) may each be provided as a separate cooking appliance (1), or may be installed as a built-in type in a cabinet such as a sink, or may be placed as a freestanding type.

[0074] The present invention is not limited thereto, but as an example, the structure of a composite cooking appliance in which a cooktop (20) is positioned on the upper side of an oven section (10) and integrated will be described in detail below.

[0075] The oven section (10) may include a main body (11) having a cavity with an open front, and a door (12) rotatably connected to the main body (11) to open and close the cavity.

[0076] The cavity forms a cooking space, and various types of heating sources, such as heaters or burners, are placed inside to heat the cooking space and cook food.

[0077] Meanwhile, a cooktop (20) placed on the upper side of the oven section (10) can be used to place a container (not shown) containing food for cooking on the top plate (23), and the container can be indirectly heated via the top plate (23) by a heating section (22) placed on the lower side of the top plate (23).

[0078] Additionally, the cooking appliance (1) may further include an operating unit (30).

[0079] As illustrated, the operating unit (30) may be composed of a plurality of knobs (31) and may control the operation of the oven unit (10) and the cooktop (20).

[0080] Additionally, the operating unit (30) may be configured as a button, switch or touch operating device as needed.

[0081] The operating unit (30) may be placed in front of the cooktop (20) as shown or in front of the oven unit (10).

[0082] Additionally, a display (32) that visually displays the operating status of the cooking appliance (1) may be provided close to the operating unit (30).

[0083] Below, the detailed structure of the cooktop (20) will be described in detail with reference to FIGS. 2 to 5.

[0084] Figure 2 is an exploded perspective view showing a cooktop (20) according to one embodiment of the present invention.

[0085] As shown, the cooktop (20) may be configured to include a top plate (23) on which a container is mounted on the upper surface, a heating element (22) disposed on the lower side of the top plate (23), and a base plate (21) that supports the heating element (22) and the top plate (23).

[0086] The base plate (21) can be formed to have an overall rectangular shape, and can function as a frame that forms the overall structure of the cooktop (20) and supports the heating unit (22) and the top plate (23).

[0087] As shown, the base plate (21) can provide a structure on which a heating unit (22) and a top plate (23) can be mounted.

[0088] To this end, the base plate (21) can be formed by processing a metal plate so that it has a predetermined rigidity and the influence of heat generated from the heating unit (22) can be minimized.

[0089] In the case of a type in which the cooktop (20) is installed independently, the base plate (21) may form the exterior of the remaining portion of the cooktop (20) except for the upper surface. In this case, the base plate (21) may be referred to as a case because it may form the exterior of the cooktop (20).

[0090] A mounting hole (212) for mounting a heating unit (22) may be formed vertically through the base plate (21). The heating unit (22) may be positioned in such a way that it passes through the mounting hole (212) and is partially inserted into the mounting hole (212).

[0091] At this time, in order to minimize the heat generated from the heating unit (22) from being transferred to the base plate (21) and to enable the heating unit (22) to be elastically supported, the heating unit (22) may be connected to the mounting hole (212) via a plurality of springs (24). Although Fig. 2 illustrates a configuration in which the heating unit (22) is elastically supported via a pair of springs (24), this is merely exemplary, and the number of springs (24) provided may be adjusted differently depending on the size or weight of the heating unit (22).

[0092] As described later, a plurality of fastening holes (2212h) may be formed on the bottom surface (2212) of the case (221) of the heating unit (22) so that each spring (24) can be fixed.

[0093] A cooktop (20) may be equipped with a plurality of heating elements (22). In this case, when a plurality of heating elements (22) are equipped, a plurality of mounting holes (212) may be formed through the base plate (21) corresponding to the number of heating elements (22).

[0094] Meanwhile, a top plate (23) can be mounted on the base plate (21).

[0095] The top plate (23) forms the upper surface of the cooktop (20), and the open upper surface of the heating element (22) can be shielded by the top plate (23) when mounted on the base plate (21).

[0096] For mounting the top plate (23), a mounting portion (211) that is formed to be sunken in a downward direction may be formed on the base plate (21). The mounting portion (211) may be sunken in a size corresponding to that of the top plate (23).

[0097] Additionally, the recessed depth of the mounting portion (211) may correspond to the thickness of the top plate (23). At this time, as illustrated, a plurality of mounting holes (212) may be located in the inner region of the mounting portion (211).

[0098] Meanwhile, FIGS. 3 to 5 illustrate the detailed configuration of individual heating elements (22) constituting the cooktop (20).

[0099] As described above, the heating element (22) can be elastically fixed and mounted to the base plate (21) via a spring (24) in such a way that it passes through the mounting hole (212) and is partially inserted into the mounting hole (212).

[0100] The heating unit (22) has the function of directly or indirectly heating a container placed on the upper surface of the top plate (23), and can be configured in various ways depending on the type of heat source. Therefore, the heating unit (22) may also be referred to as a heater unit or a burner unit.

[0101] The heating unit (22) may be composed of at least one of a sealed type heater, a radiant type heater, or an induction type heater, depending on the heat source.

[0102] FIGS. 3 to 5 illustrate the configuration of a heating unit (22) configured as a radiant type heater. Hereinafter, the configuration of the heating unit (22) configured as a radiant type heater as illustrated will be described based on the configuration thereof.

[0103] The heating unit (22) may be configured to include a heating coil (223) that generates heat when power is supplied, an insulating material (222, 226) on which the heating coil (223) is mounted, and a case (221) that is bonded to the outer surface of the insulating material (222, 226) to protect the insulating material (222, 226) and the heating coil (223).

[0104] The heating coil (223) is heated by power supply and performs the function of generating high-temperature heat.

[0105] At this time, the heat generated from the heating coil (223) can pass through the top plate (23) and be transferred to the container by radiation or conduction to heat the container.

[0106] The heating coil (223) is configured to generate heat by electrical resistance, and can be formed by winding multiple times so that the inner diameters have different circular shapes.

[0107] More specifically, as shown in FIGS. 3 to 5, the heating coil (223) is not formed in a perfect circle, but may have an overall circular shape.

[0108] In order to maximize the heat generation by maximizing the surface area, the heating coil (223) may have a repeatedly bent shape.

[0109] For example, the heating coil (223) may be repeatedly bent in a zigzag shape when viewed from above and may be extended to have an overall circular ring shape.

[0110] Additionally, in order to maximize the heat generation, the heating coil (223) may be arranged in a concentric manner with circular ring shapes of different diameters.

[0111] Meanwhile, the heating coil (223) may be configured to be divided into an internal coil (224) and an external coil (225). Accordingly, the amount of heat for heating the container can be controlled and provided according to the combination of the on / off operations of the internal coil (224) and the external coil (225).

[0112] The heating coil (223) can be supported and fixed by the insulating pad (222) in a state where it is placed on the upper surface of the insulating pad (222) constituting the insulating material (222, 223).

[0113] More specifically, the insulation (222, 226) may include an insulation pad (222) configured in a disc shape as illustrated in FIG. 5.

[0114] The insulation pad (222) can be placed inside the case (221) in a state where it is entirely accommodated inside the case (221) described later.

[0115] When power is supplied to the heating coil (223), the surface temperature of the heating coil (223) can rise to a maximum of about 2000°C.

[0116] The insulating pad (222) can be formed of a non-flammable insulating material suitable for the high temperature environment formed by the heating coil (223).

[0117] In this way, as the heating coil (223) is placed on the upper surface of the insulating pad (222) made of a non-combustible insulating material, heat transfer in the downward direction when the heating coil (223) generates heat can be minimized. In addition, the heating coil (223) can be placed on the upper surface of the insulating pad (222).

[0118] Meanwhile, the insulation material (222, 226) may further include an insulation ring (226) formed in a circular ring shape as illustrated in FIG. 5.

[0119] As with the insulation pad (222), the insulation ring (226) may be formed of a non-combustible insulation material to be suitable for the high temperature environment formed by the heating coil (223).

[0120] At this time, the insulating ring (226) may be arranged along the outer edge of the insulating pad (222) and positioned to be coupled to the outer edge of the insulating pad (222).

[0121] Accordingly, as the insulation ring (226) is coupled to the insulation pad (222), a receiving space (S) in which the heating coil (223) can be entirely received can be formed on the radially inner side of the insulation ring (226) and the upper side of the insulation pad (222).

[0122] Meanwhile, the upper end of the insulation ring (226) can be placed so as to be in surface contact with the lower surface of the top plate (23).

[0123] At this time, the upper end of the insulation ring (226) can be maintained in elastic contact with the lower surface of the top plate (23) by the pressure of the spring (24) described above.

[0124] Accordingly, the space between the insulating ring (226) and the top plate (23) can be effectively sealed by the spring (24), so that the heat inside the heating part (22) can be minimized from being released to the outside of the heating part (22) by convection.

[0125] Meanwhile, the case (221) is coupled to the outside of the insulation (222, 226) and serves to protect the insulation (222, 226) and the heating coil (223).

[0126] In order to accommodate and protect the insulation pad (222) and the insulation ring (226) inside, the case (221) can be formed into a cylindrical shape with an open upper surface.

[0127] In this way, the case (221) can be formed by pressing a plate having a predetermined metal material to effectively protect the insulation pad (222) and insulation ring (226) that are relatively weak in rigidity, while being suitable for a high-temperature environment.

[0128] As it is provided with an overall cylindrical shape, the case (221) can be configured to include a bottom surface portion (2212) in the shape of a disc and a cylindrical surface portion (2211) in the shape of a cylinder extending upward along the outer edge of the bottom surface portion (2212).

[0129] The cylindrical surface (2211) of the case (221) may be provided in a cylindrical shape corresponding to the shape of the outer surface of the insulating pad (222) and the outer surface of the insulating ring (226).

[0130] At this time, the outer surface of the insulation pad (222) is completely covered by the cylindrical surface (2211), but the outer surface of the insulation ring (226) may be partially covered.

[0131] That is, as described above, so that the insulation ring (226) can be in surface contact with the lower surface of the top plate (23), the upper end of the cylindrical surface portion (2211) can be formed at a position lower in the vertical direction than the upper end of the insulation ring (226).

[0132] Accordingly, the insulation ring (226) may be exposed to the outside at a portion corresponding to the upper surface of the insulation ring (226) and the upper surface of the cylindrical surface (2211) in the vertical direction.

[0133] The bottom surface (2212) of the case (221) may include a first bottom surface (2212a) connected to the lower edge of the cylindrical surface (2211), and a second bottom surface (2212b) positioned radially inward from the first bottom surface (2212a).

[0134] As shown, the second bottom surface (2212b) can be formed concavely toward the downward direction so as to be formed at a lower position in the vertical direction than the second bottom surface (2212b).

[0135] The horizontal width of the first bottom surface (2212a) may correspond to the horizontal thickness of the aforementioned insulation ring (226), and the area of ​​the second bottom surface (2212b) may correspond to the area occupied by the heating coil (223).

[0136] In this way, by forming the second bottom surface (2212b) having an area corresponding to the area occupied by the heating coil (223) in a concave downward direction, the vertical height of the receiving space (S) in which the heating coil (223) is installed can be expanded, and as described later, a free space can be secured to allow the thermostat (2271) to be installed.

[0137] Meanwhile, a fastening hole (2212h) may be formed on the first bottom surface (2212a) to fasten the aforementioned spring (24).

[0138] One end of the spring (24) can be fastened to the fastening hole (2212h) of the first bottom surface (2212a) through a fastening means not shown, such as a screw bolt.

[0139] However, as described above, the number of springs (24) provided may be set differently depending on the size or weight of the heating unit (22).

[0140] In order to secure the diversity and tolerance of the design that can be set differently according to the shape and weight of the heating part (22), a plurality of fastening holes (2212h) can be formed to be arranged along the circumferential direction on the first bottom surface (2212a), and the circumferential spacing between each fastening hole (2212h) can be set in various ways.

[0141] Meanwhile, the heating unit (22) may further include an overheating prevention device (227) placed on the outside of the case (221).

[0142] More specifically, as illustrated in FIGS. 3 to 5, the overheating prevention device (227) may include a thermostat (2271) extending from the outside of the case (221) toward the internal receiving space (S) of the insulation (222, 226), and a housing (2272) disposed on the outside of the case (221).

[0143] As shown, the thermostat (2271) may be provided in a rod shape, and one end of the rod shape may be placed inside the housing (2272) and the other end of the rod shape may be placed on the central side of the internal receiving space (S).

[0144] That is, the thermostat (2271) can be extended from the upper side of the heating coil (223) to cross the heating coil (223) and detects whether the receiving space (S) in which the heating coil (223) is placed is overheated.

[0145] Although not shown, inside the housing (2272) there is a pair of terminals (2273) that supply power to the heating coil (223) and a switch that makes and breaks an electrical connection between the power supply.

[0146] Accordingly, when overheating or overload occurs in the heating coil (223) or the receiving space (S) and the temperature rises above a predetermined set temperature, the switch placed inside the housing (2272) is opened by the thermostat (2271), and the power supply to the heating coil (223) is immediately cut off.

[0147] Any means known in the art can be applied to the detailed configuration of the overheating prevention device (227), so a description of the detailed configuration is omitted below.

[0148] Meanwhile, although not shown, the heating unit (22) of the cooking appliance according to the present invention may further include a heat efficiency improvement unit (25) as a means for improving the heat generation efficiency and power efficiency of the heating coil (223).

[0149] Referring to FIGS. 6 to 19 below, the detailed configuration of the thermal efficiency improvement unit (25) for each embodiment will be described.

[0150] [Example 1: Detailed configuration of heating unit with first external insulation]

[0151] Figures 6 and 7 illustrate a configuration in which a heat efficiency improvement unit (25) according to the first embodiment of the present invention is provided.

[0152] As described above, the purpose of the present invention is to improve the heat generation efficiency of the heating coil (223) constituting the heating unit (22) through the heat efficiency improvement unit (25).

[0153] FIGS. 6 and 7 illustrate a first external insulation material (251) disposed on the outside of a case (221) as a first embodiment of a thermal efficiency improvement unit (25).

[0154] The first external insulation (251) serves to minimize the heat generated from the heating coil (223) from being released through the bottom surface (2212) of the case (221).

[0155] To this end, as illustrated, the first external insulation material (251) may be bonded to the outside of the bottom surface (2212) of the case (221) and placed to cover the bottom surface (2212) of the case (221) from the outside of the case (221).

[0156] In order to maximize the insulation effect on the bottom surface (2212) of the case (221) and the heat retention effect on the case (221), the first external insulation material (251) can be arranged to completely cover the first bottom surface (2212a) and the second bottom surface (2212b) constituting the bottom surface (2212) of the case (221) from the outside.

[0157] Accordingly, corresponding to the bottom surface (2212) of the case (221) having a circular shape, the first external insulation material (251) can be configured as a circular pad having a predetermined thickness.

[0158] Meanwhile, as shown, the first external insulation material (251) is placed on the outside of the bottom surface (2212) of the case (221).

[0159] Therefore, it is placed in a lower temperature environment than the insulation pad (222) and insulation ring (226) that are placed inside the case (221) and directly exposed to the heat generation of the heating coil (223).

[0160] Therefore, the first external insulation material (251) can be formed of a material having a heat resistance temperature lower than the heat resistance temperatures of the insulation pad (222) and the insulation ring (226).

[0161] However, in order to prevent the risk of fire due to overheating of the heating coil (223), it is preferable that it be formed of a non-combustible insulating material, similar to the insulating pad (222) and the insulating ring (226).

[0162] Meanwhile, as described above, the first external insulation material (251) is attached to the outside of the bottom surface (2212) of the case (221).

[0163] The first external insulation material (251) may be configured to be directly fixed to the bottom surface (2212) of the case (221) using an adhesive or the like, but there is a high possibility that the adhesive will be affected by the heat generated by the heating coil (223).

[0164] Therefore, as a means for fixing the first external insulation material (251) to the bottom surface (2212) of the case (221), a first holder (252) that fixes the first external insulation material (251) to the bottom surface (2212) of the case (221) may be included.

[0165] For example, FIGS. 6 and 7 illustrate a configuration in which the first holder (252) is formed in a single circular ring shape extending along the outer edge of the first external insulation material (251).

[0166] However, this is merely an example, and a configuration in which the first holder (252) is divided into multiple pieces is also within the scope of the present invention. The present invention is not limited thereto, but the following description will be made based on a configuration in which the first holder (252) is provided in a single circular ring shape.

[0167] At this time, the outer diameter of the first holder (252) having a ring shape may have a dimension that is equal to or slightly smaller than the diameter of the bottom surface (2212) of the case (221).

[0168] Additionally, the inner diameter of the first holder (252) having a ring shape may have a dimension smaller than or equal to the inner diameter of the first bottom surface (2212a) constituting the bottom surface (2212) of the case (221).

[0169] Accordingly, the radial width of the first holder (252) can be formed to be equal to or slightly smaller than the radial width of the first bottom surface (2212a) of the bottom surface portion (2212).

[0170] In addition, as illustrated in FIG. 6, the thickness of the first holder (252) may be maintained uniformly along the circumferential direction, but may be formed to be smaller than or equal to the height at which the second bottom surface (2212b) protrudes from the first bottom surface (2212a).

[0171] In this way, by forming the radial width of the first holder (252) to be smaller than or equal to the radial width of the first bottom surface (2212a) and the thickness of the first holder (252) to be smaller than or equal to the protrusion height of the second bottom surface (2212b), it is possible to provide a uniform fixing force along the circumferential direction to the first external insulation material (251) while minimizing interference with other components constituting the cooktop (20).

[0172] Meanwhile, the first holder (252) may be provided with a first through hole (252h) formed to penetrate toward the first bottom surface (2212a) among the bottom surface portions (2212) of the case (221).

[0173] At this time, as shown, a plurality of fastening holes (2212h) for fixing a spring (24) can be formed through the first bottom surface (2212a) of the bottom surface (2212) of the case (221).

[0174] As described above, in order to secure design diversity and tolerance that can be set differently depending on the shape and weight of the heating unit (22), a plurality of fastening holes (2212h) can be formed to be arranged along the circumferential direction on the first bottom surface (2212a), and the number of fastening holes (2212h) is much greater than the number of springs (24).

[0175] The first holder (252) according to the first embodiment of the present invention can be fixed through a fastening hole (2212h) that has already been formed, so that the first through hole (252h) of the first holder (252) can be formed at a position corresponding to some of the fastening holes (2212h) among the plurality of fastening holes (2212h).

[0176] However, in order to avoid interference with the fixing and installation of the spring (24), some of the fastening holes (2212h) may be selected as unused fastening holes (2212h) to which the spring (24) is not fastened.

[0177] The first holder (252) can be fixed by a fastener, such as a screw bolt, which can pass through the first through hole (252h), the first external insulation material (251), and the unused fastening hole (2212h) simultaneously.

[0178] [Example 2: Detailed configuration of heating unit with second external insulation]

[0179] Figures 8 to 10 illustrate a configuration in which a heat efficiency improvement unit (25) according to the second embodiment of the present invention is provided.

[0180] FIGS. 8 to 10 illustrate a second external insulation material (253) disposed on the outside of the case (221) as a second embodiment of the thermal efficiency improvement unit (25).

[0181] The second external insulation (253) serves to minimize the heat generated from the heating coil (223) from being released through the cylindrical surface (2211) of the case (221).

[0182] To this end, as illustrated, the second external insulation material (253) may be bonded to the outside of the cylindrical surface portion (2211) of the case (221) and placed to cover the cylindrical surface portion (2211) of the case (221) from the outside of the case (221).

[0183] In order to maximize the insulation effect and heat retention effect for the case (221) and the insulation ring (226) that serves as the internal insulation, the second external insulation material (253) can be arranged to completely cover the cylindrical surface (2211) of the case (221) and the insulation ring (226) from the outside.

[0184] Accordingly, corresponding to the cylindrical surface (2211) and the insulating ring (226) of the case (221) having a cylindrical shape, the second external insulating material (253) can be configured as a cylindrical pad having a predetermined thickness.

[0185] However, in order to prevent interference with the overheating prevention device (227) described above, the second external insulation material (253) may be formed to have a C-shaped cross-section rather than a complete cylinder so as to avoid the location where the housing (2272) and terminal (2273) of the overheating prevention device (227) are formed.

[0186] Meanwhile, as shown, the second external insulation material (253) is placed on the outside of the cylindrical surface (2211) of the case (221) and the insulation ring (226).

[0187] Therefore, since the second external insulation material (253) is placed in a lower temperature environment than the insulation pad (222) and the insulation ring (226), like the first external insulation material (251), it can be formed of a material having a heat resistance temperature lower than the heat resistance temperatures of the insulation pad (222) and the insulation ring (226).

[0188] However, in order to prevent the risk of fire due to overheating of the heating coil (223), it may be formed of a non-combustible insulating material, similar to the insulating pad (222) and the insulating ring (226). Preferably, it may be formed of the same material as the first external insulating material (251).

[0189] Meanwhile, as described above, the second external insulation material (253) is attached to the outside of the cylindrical surface (2211) of the case (221).

[0190] The second external insulation material (253) may be configured to be directly fixed to the cylindrical surface (2211) of the case (221) using an adhesive or the like, but, like the first external insulation material (251), the adhesive is likely to be affected by the heat generation of the heating coil (223).

[0191] Therefore, as a means for fixing the second external insulation material (253) to the bottom surface (2212) of the case (221), a second holder (254) that fixes the second external insulation material (253) to the cylindrical surface (2211) of the case (221) may be included.

[0192] For example, FIGS. 8 to 10 illustrate a configuration in which the second holder (254) is formed in a single cylindrical shape extending along the outer circumference of the second external insulation material (253).

[0193] However, this is merely an example, and a configuration in which the second holder (254) is divided into multiple pieces similar to the first holder (252) is also naturally within the scope of the present invention. The present invention is not limited thereto, but the following description will be made based on an example in which the second holder (254) is provided in a single circular ring shape.

[0194] At this time, the vertical width of the second holder (254) having a cylindrical shape may have a dimension that is the same as or slightly smaller than the vertical width of the second external insulation material (253).

[0195] In this way, by forming the vertical width of the second holder (254) to be smaller than or equal to the vertical width of the second external insulation material (253), the second holder (254) does not protrude from the heating unit (22) in the vertical direction, thereby minimizing interference with other components forming the cooktop (20) and providing a uniform fixing force along the circumferential direction to the second external insulation material (253).

[0196] Meanwhile, the second holder (254) may be provided with a connecting tab (254a) that is formed by bending toward the first bottom surface (2212a) among the bottom surface portions (2212) of the case (221).

[0197] That is, the connecting tab (254a) may be a free end in which one end is integrally formed at the lower edge of the second holder (254) and the other end is bent and extended toward the first bottom surface (2212a).

[0198] Although FIGS. 9 and 10 illustrate an embodiment in which a total of three connection tabs (254a) are provided, this is merely exemplary and the number of connection tabs (254a) may be added or reduced depending on the size of the heating unit (22).

[0199] Each connecting tab (254a) may be provided with a second through hole (254h) formed through the first bottom surface (2212a).

[0200] At this time, as described above, a plurality of fastening holes (2212h) for fixing the spring (24) can be formed through the second bottom surface (2212b) of the bottom surface (2212) of the case (221), and similarly to the first holder (252), the second holder (254) can be fixed through the already formed fastening holes (2212h) so that the second through hole (254h) of the connecting tab (254a) can be formed at a position corresponding to some of the fastening holes (2212h) among the plurality of fastening holes (2212h).

[0201] However, in order to prevent interference with the fixing and installation of the spring (24), some of the fastening holes (2212h) to which the connecting tab (254a) is fixed may be selected as unused fastening holes (2212h) to which the spring (24) is not fixed.

[0202] The connecting tab (254a) of the second holder (254) can be fixed through a fastener, such as a screw bolt, that can pass through the second through hole (254h), the second external insulation material (253), and the unused fastening hole (2212h) at the same time.

[0203] [Third embodiment: Detailed configuration of a heating unit having a first external insulation material and a second external insulation material]

[0204] Although the above-described heating unit (22) has been described as having only one of the first external insulation material (251) according to the first embodiment and the second external insulation material (253) according to the second embodiment, the heating unit (22) may be configured to have both the first external insulation material (251) according to the first embodiment and the second external insulation material (253) according to the second embodiment.

[0205] In this way, when both the first external insulation material (251) according to the first embodiment and the second external insulation material (253) according to the second embodiment are provided, the insulation effect and heat retention effect for the heating unit (22) can be further improved compared to when only one of the first external insulation material (251) and the second external insulation material (253) is provided.

[0206] At this time, the first external insulation material (251) and the second external insulation material (253) may be configured to be integrally formed with each other and attached to the outer surface of the case (221).

[0207] Fig. 11 illustrates a third embodiment of a thermal efficiency improvement unit (25) in which a first external insulation material (251) and a second external insulation material (253) are integrated and placed on the outside of a case (221).

[0208] As the first external insulation material (251) and the second external insulation material (253) are provided as an integral unit in this way, heat can be suppressed from being released through the gap between the first external insulation material (251) and the second external insulation material (253) when the first external insulation material (251) and the second external insulation material (253) are provided separately, thereby further improving the insulation effect and the heat preservation effect.

[0209] In addition, when the first external insulation material (251) and the second external insulation material (253) are provided separately, the first holder (252) and the second holder (254) must be provided, respectively. However, when the first external insulation material (251) and the second external insulation material (253) are provided as an integral unit, they can be fixed to the case (221) through a single holder, so the configuration can be expected to be simplified.

[0210] At this time, although not shown in FIG. 11, the means for fixing the integrated first external insulation material (251) and second external insulation material (253) to the case (221) may be more suitable as the second holder (254) shown in FIG. 9 and FIG. 11.

[0211] This is because, when the first external insulation material (251) and the second external insulation material (253) integrated with only the first holder (252) are attached to the case (221), there is a possibility that the second external insulation material (253) may not be effectively supported and fixed.

[0212] [Example 4: Detailed configuration of a heating unit equipped with a reflector]

[0213] Figures 12 to 19 illustrate a configuration in which a heat efficiency improvement unit (25) according to the fourth embodiment of the present invention is provided.

[0214] First, referring to FIGS. 12 and 13, a fourth embodiment of a heat efficiency improvement unit (25) is illustrated, in which a reflector (255) is placed inside a receiving space (S) formed by an insulating pad (222) and an insulating ring (226).

[0215] The heat generated from the heating coil (223) placed inside the receiving space (S) formed by the insulating pad (222) and the insulating ring (226) is mostly transferred to the lower surface of the top plate (23) in the form of radiant heat, and the radiant heat transferred to the top plate (23) is used to heat the container.

[0216] In this way, a portion of the radiant heat generated from the heating coil (223) is transmitted toward the inner surface of the receiving space (S), and the reflector (255) according to the fourth embodiment of the present invention reflects the radiant heat transmitted toward the inner surface of the receiving space (S) toward the lower surface of the top plate (23), thereby improving the thermal efficiency of the heating coil (223).

[0217] To maximize the reflection efficiency for the radiant heat, the reflector (255) can be arranged to completely cover the inner surface of the receiving space (S) from the inside.

[0218] Therefore, in response to the inner surface of the receiving space (S) having a cylindrical shape, the reflector (255) can be configured in a cylindrical shape having a predetermined thickness.

[0219] In order to prevent interference with the overheating prevention device (227) described above, the second external insulation material (253) may be formed to have a C-shaped cross-section rather than a complete cylinder so as to avoid the location where the thermostat (2271) of the overheating prevention device (227) is formed.

[0220] However, although the configuration in which the reflector (255) is provided in a continuous ring shape having an overall C-shape is disclosed in FIG. 13 and below, this is merely exemplary, and it may be provided in a partially cut ring shape or in a polygonal inner plate shape in which a plurality of plate members are continuously or discontinuously arranged. The present invention is not limited thereto, but the following description will be made based on a configuration in which the reflector (255) is provided in a continuous ring shape having an overall C-shape.

[0221] Additionally, a predetermined notch (2555) may be formed at the leading edge (2551) or the trailing edge (2552) of the reflector (255) so as to avoid a pair of terminals (2273) extending toward the inside of the receiving space (S).

[0222] In order to completely cover the inner surface of the receiving space (S) from the inside, the reflector (255) is arranged between the inner surface of the receiving space (S) and the heating coil (223) based on the horizontal direction, and the lower edge (2557) of the reflector (255) extends to contact the lower surface of the receiving space (S), that is, the upper surface of the insulating pad (222), and the upper edge (2556) of the reflector (255) can extend to the position of the upper surface of the receiving space (S), that is, the upper surface of the insulating ring (226).

[0223] Meanwhile, the reflector (255) is directly exposed to the high temperature environment formed by the heating coil (223) and is placed at a position where it is heated by the radiant heat of the heating coil (223).

[0224] Therefore, it can be formed of a metal material having much higher heat resistance than the case (221), first holder (252) and second holder (254) described above, and preferably, it can be formed through press processing of a plate material having a stainless steel material.

[0225] However, since there is a high possibility of damage by the conductive heat of the heating coil (223) and a high possibility of a short circuit occurring when in contact with the heating coil (223) through which current flows, the reflector (255) must be kept separated from the heating coil (223) and may be placed in close contact with the inner surface of the receiving space (S).

[0226] To this end, the reflector (255) is formed to have a thickness smaller than the gap between the inner surface of the receiving space (S) and the heating coil (223) arranged at the outermost side in the horizontal direction.

[0227] Meanwhile, as described above, the reflector (255) serves to reflect the radiant heat generated from the heating coil (223) toward the top plate (23).

[0228] In order to increase the reflection efficiency of the top plate (23), the inner surface (2553) of the reflector (255) arranged toward the heating coil (223) can be configured to have a higher reflectivity than the outer surface (2554) arranged toward the inner surface of the receiving space (S).

[0229] In order for the inner surface (2553) of the reflector (255) to have a higher reflectivity than the outer surface (2554), the inner surface (2553) of the reflector (255) may be surface-processed to have a lower surface roughness than the outer surface (2554), or, as illustrated in FIG. 13, a coating layer (2553c) may be formed on the inner surface (2553) of the reflector (255) with a material having a higher reflectivity.

[0230] At this time, the coating layer (2553c) may be selected from a material having heat resistance that is not damaged or affected by the radiant heat of the heating coil (223).

[0231] As described above, the reflector (255) can be placed in the receiving space (S) so that the outer surface (2554) is in close contact with the inner surface of the receiving space (S).

[0232] As the reflector (255) is placed in close contact with the inner surface of the receiving space (S), the rigidity of the inner side of the heating part (22) can also be additionally reinforced.

[0233] As illustrated in Fig. 13, the reflector (255) can be formed to have an outer diameter larger than the inner diameter of the inner surface of the receiving space (S).

[0234] Accordingly, when the reflector (255) is inserted into the receiving space (S), the outer diameter of the reflector (255) can be reduced to the same level as the inner diameter of the receiving space (S).

[0235] Through this, when the reflector (255) is settled in the receiving space (S), the reflector (255) maintains a close contact state with the inner surface of the receiving space (S) by its own restoring force to return to its original shape, and at least horizontal movement of the reflector (255) can be blocked.

[0236] However, through the self-restoring force of the reflector (255), a state in which the vertical movement of the reflector (255) is not completely blocked may be formed. In other words, the reflector (255) may be incompletely fixed.

[0237] As a means for forming a secure fixation state of the reflector (255) to the receiving space (S), a fixing means may be added to the reflector (255).

[0238] The fixing means of the reflector (255) may include a front fixing part (2551a), a rear fixing part (2552a), and a bottom fixing part (2559).

[0239] In Fig. 13, the tip fixing part (2551a) and the bottom fixing part (2559) that serve as fixing means for the reflector (255) are illustrated.

[0240] As illustrated, a leading edge (2551) which is one end of the reflector (255) and a trailing edge (2552) which is the other end, and a wedge-shaped leading edge fixing part (2551a) and a trailing edge fixing part (2552a) which are formed by bending toward the inner surface and having a receiving space (S) at a lower edge (2557) adjacent to the leading edge (2551) and the trailing edge (2552) respectively, may be integrally provided in the reflector (255).

[0241] The insulating ring (226) and the insulating pad (222) constituting the internal insulating material of the heating unit (22) of the present invention can be formed of a flexible material having a strength similar to that of gypsum, but much lower than that of the reflector (255).

[0242] Accordingly, the wedge-shaped leading edge fixing portion (2551a) and the trailing edge fixing portion (2552a) can penetrate the surface of the insulating ring (226) and the insulating pad (222) even with a relatively weak pressing force and can be easily embedded into the interior of the insulating ring (226) and the insulating pad (222), thereby enabling the leading edge (2551) and the trailing edge (2552) of the free end of the reflector (255) to be effectively and easily fixed to the insulating ring (226) or the insulating pad (222).

[0243] Meanwhile, the lower fixing part (2559) of the reflector (255) may be provided in a wedge shape similar to the front fixing part (2551a) and the rear fixing part (2552a).

[0244] However, unlike the front fixing part (2551a) and the rear fixing part (2552a), it may be arranged along the lower edge (2557) of the reflector (255) so as to extend downward so as to penetrate the surface of the upper surface of the insulating pad (222) and be embedded in the interior of the insulating pad (222).

[0245] At this time, the spacing between each lower fixing member (2559) can be formed approximately equally so as to provide a uniform fixing force in the circumferential direction to the lower edge (2557) of the reflector (255).

[0246] Figure 16 shows a cross-sectional view taken along a vertical plane with the reflector (255) placed in the receiving space (S).

[0247] As illustrated in FIG. 16, the inner surface of the reflector (255) may be configured as a vertical plane that is arranged parallel to the inner surface of the insulating ring (226) so that the reflector (255) can effectively cover the inner surface of the insulating ring (226) forming the receiving space (S).

[0248] At this time, as shown, at least the upper edge (2556) of the reflector (255) is positioned at the same position as the upper surface of the insulation ring (226) in the vertical direction, so it can be positioned at a higher position in the vertical direction than the heating coil (223) that is mounted on the upper surface of the insulation pad (222).

[0249] Accordingly, the radiant heat (H) generated from the heating coil (223) placed adjacent to the reflector (255) and radiated toward the inner surface of the insulation ring (226) can be effectively converted so that the direction of movement is toward the lower surface of the top plate (23) by being reflected on the inner surface (2553) of the reflector (255).

[0250] At this time, as shown in FIGS. 17 and 18, the cross-section of the reflector (255) may be configured as an inclined plane or a curved plane rather than a vertical plane as shown in FIG. 16.

[0251] In this way, by configuring the cross-section of the reflector (255), the inner peripheral surface (2553) of the reflector (255) positioned toward the heating coil (223) can be configured as an inclined surface or a curved surface.

[0252] As shown, since the inner surface (2553) of the reflector (255) is configured as an inclined surface or a curved surface, the path of movement of the radiant heat (H) to the lower surface of the top plate (23) can be shortened compared to when it is configured as a vertical surface, and thus the heat generation efficiency of the heating coil (223) can be further improved.

[0253] Meanwhile, as illustrated in FIG. 17, when the inner surface (2553) of the reflector (255) is configured as an inclined surface, the inclination angle (a) of the reflector (255) can be set in consideration of the thickness of the reflector (255) and the horizontal distance between the inner surface of the insulating ring (226) and the outermost heating coil (223), and the inclination angle (a) can be set to have an angle range of approximately 3 to 5 degrees.

[0254] In addition, when the inner surface (2553) of the reflector (255) is formed as a curved surface as illustrated in FIG. 18, the radius of curvature of the inner surface (2553) of the reflector (255) can be set to gradually increase as it progresses from the lower edge (2557) toward the upper edge (2556) for the same reason.

[0255] FIG. 19 illustrates a configuration in which the inner surface (2553) and the outer surface (2554) of the reflector (255) are configured as vertical surfaces, similar to FIG. 17, but a protrusion (2558) is added to the outer surface (2554) of the reflector (255).

[0256] In this way, by adding a protrusion (2558) to the outer surface (2554) of the reflector (255), a predetermined separation space (S1) can be formed between the inner surface of the insulating ring (226) forming the inner surface of the receiving space (S) and the outer surface (2554) of the reflector (255).

[0257] Since the predetermined separation space (S1) forms an air layer, it has the effect of adding an insulation layer that can increase the heat generation efficiency of the heating coil (223) between the inner surface of the insulation ring (226) and the outer surface (2554) of the reflector (255).

[0258] In order to form a space (S1) uniformly along the circumferential direction, a plurality of protrusions (2558) may be provided, and the circumferential spacing between each protrusion (2558) may be formed to be approximately equal.

[0259] As described above, in order to prevent contact between the inner surface of the reflector (255) and the heating coil (223), the height of the projection (2558) protruding from the outer surface (2554) of the reflector (255) in the horizontal direction and the thickness of the reflector (255) can be formed to be smaller than the horizontal distance between the inner surface of the insulating ring (226) and the outermost heating coil (223).

[0260] Meanwhile, the protrusion (2558) added to the outer surface of the reflector (255) can be formed integrally with the reflector (255) through press forming, such as an embossing shape, a bead forming shape, a cutting protrusion, etc.

[0261] Although the present invention has been described with reference to the drawings exemplified above, it is to be understood that the present invention is not limited to the embodiments and drawings disclosed herein, and that various modifications may be made by those skilled in the art within the scope of the technical idea of ​​the present invention. Furthermore, even if the operational effects according to the configuration of the present invention have not been explicitly described while describing the embodiments of the present invention, it is natural that the effects predictable by the corresponding configuration should also be acknowledged.

Claims

1. Heating section; and A top plate that shields the heating element from the upper side and on which a container for cooking is placed; In a cooking appliance including: The above heating part, A heating coil that generates heat by electrical resistance; Insulating material housing said heating coil inside; A case bonded to the outer surface of the above insulation; and A heat efficiency improving unit arranged inside the above insulation material or outside the above case and improving the heat generation efficiency of the heating coil; A cooking appliance comprising:

2. In paragraph 1, The above thermal efficiency improvement part is, A first external insulating material coupled to the outer side of the bottom surface of the case and covering the bottom surface of the case; A cooking appliance comprising:

3. In paragraph 2, The above heating part, A first holder for fixing the first external insulation material to the bottom surface of the case; A cooking appliance further comprising:

4. In paragraph 3, The first holder is provided with a first through hole formed through the bottom surface of the case, A cooking appliance having a fastening hole formed through a hole in the bottom surface of the case at a position corresponding to the first through hole.

5. In paragraph 2, A cooking appliance wherein the first external insulation material has a lower heat-resistant temperature than the insulation material.

6. In paragraph 1, The above thermal efficiency improvement part is, A second external insulating material coupled to the outer side of the cylindrical surface of the case and covering the cylindrical surface of the case; A cooking appliance comprising:

7. In paragraph 6, The above heating part, A second holder for fixing the second external insulation material to the cylindrical surface of the case; A cooking appliance further comprising:

8. In paragraph 7, The second holder has a connecting tab formed by bending toward the bottom surface of the case, The above connecting tab is provided with a second through hole formed through the bottom surface of the case, A cooking appliance in which the bottom surface of the above case is provided with a fastening hole formed through the upper and lower direction at a position corresponding to the above second through hole.

9. In paragraph 6, A cooking appliance wherein the second external insulation material has a lower heat-resistant temperature than the insulation material.

10. In paragraph 1, The above thermal efficiency improvement part is, A first external insulating material coupled to the outer side of the bottom surface of the case and covering the bottom surface of the case; and A second external insulating material coupled to the outer side of the cylindrical surface of the case and covering the cylindrical surface of the case; Including, A cooking appliance in which the first external insulation material and the second external insulation material are formed integrally.

11. In paragraph 1, The above thermal efficiency improvement part is, A reflector provided inside the insulation material and positioned between the inner surface of the insulation material and the heating coil, the reflector reflecting heat generated from the heating coil toward the top plate; A cooking appliance comprising:

12. In paragraph 11, The above reflector has an inner surface arranged toward the heating coil and an outer surface arranged toward the inner surface of the insulation material, A cooking appliance wherein the inner surface of the reflector has a higher reflectivity than the outer surface of the reflector.

13. In paragraph 12, A cooking appliance in which the inner surface of the above reflector is surface-processed to have a higher reflectivity than the outer surface of the above reflector.

14. In paragraph 12, A cooking appliance in which the inner surface of the reflector is coated with a material having a higher reflectivity than the outer surface of the reflector.

15. In paragraph 11, The above reflector has an inner surface arranged toward the heating coil and an outer surface arranged toward the inner surface of the insulation material, A cooking appliance in which the outer surface of the above reflector is placed in contact with the inner surface of the above insulating material.

16. In paragraph 15, A cooking appliance in which the inner surface of the above reflector is a vertical plane arranged parallel to the inner surface of the above insulating material.

17. In paragraph 15, A cooking appliance in which the inner surface of the above reflector is an inclined surface that is inclined toward the top plate.

18. In paragraph 15, A cooking appliance in which the inner surface of the above reflector is a curved surface formed concavely toward the top plate.

19. In paragraph 11, The above reflector has an inner surface arranged toward the heating coil and an outer surface arranged toward the inner surface of the insulation material, A cooking appliance in which a space is formed between the outer surface of the reflector and the inner surface of the insulation material.

20. In paragraph 19, A cooking appliance in which the outer surface of the above reflector is provided with a protrusion formed to protrude toward the inner surface of the above insulating material.

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