Heating regulator

Abstract

To provide a heating cooker which has heater wires hardly coming into contact with each other and can improve the heating efficiency of the outside heater.SOLUTION: A heating cooker includes: a heating chamber for heating an object to be cooked; and a plane heater constituting a heat source by an inside heater disposed on a ceiling wall of the heating chamber and an outside heater surrounding the inside heater. The outside heater is structured by winding a heater wire around an outside mica, and the inside heater is structured by winding a heater wire around the inside mica. The outside mica has a frame thick part and a frame thin part. The heater wire is laid almost like a straight line along the longitudinal direction of the frame thin part. An upper side mica covering the upper surface side of at least part of the heater wire laid over the frame thin part is further provided.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a cooking device that heats and cooks food in a heating chamber, and more particularly to a cooking device that heats food using a flat heater provided on the ceiling wall of the heating chamber. [Background technology]

[0002] The cooking means used in cooking appliances include an infrared heater unit that radiates heat rays to directly heat food, a microwave heating unit that radiates microwaves to heat food, a steam heating unit that heats food with water vapor, and a hot air circulation unit that circulates hot air inside the heating chamber to heat food.

[0003] In addition, as a heating cooking means in a heating cooker, there is a configuration in which a flat heater is provided on the ceiling wall of a rectangular parallelepiped heating chamber to heat the ceiling wall, and the interior of the heating chamber is indirectly heated by the ceiling wall (see Patent Documents 1 and 2).

[0004] There is also a configuration in which a flat heater is placed on the ceiling wall and used to increase the temperature inside the refrigerator (see Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 3-103206 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-54124 [Patent Document 3] Japanese Patent Application Laid-Open No. 2017-161163 Summary of the Invention [Problem to be solved by the invention]

[0006] However, if one tries to improve the heating efficiency of not only the inner heater but also the outer heater, it becomes necessary to arrange a heater wire over almost the entire outer mica of the outer heater.

[0007] An object of the present invention is to provide a cooking device in which heater wires are less likely to come into contact with each other and the heating efficiency of the outer heater can be improved. [Means for solving the problem]

[0008] A cooking device according to one aspect of the present invention includes: A heating chamber for heating food to be cooked; A cooking device comprising an inner heater disposed on a ceiling wall of a heating chamber and a flat heater constituting a heat source by an outer heater surrounding the inner heater, The outer heater is configured by winding a heater wire around an outer mica, and the inner heater is configured by winding a heater wire around an inner mica, The outer mica has a thick frame portion and a thin frame portion, A heater wire is laid substantially linearly along the longitudinal direction of the frame detail, The heater further includes upper mica covering the upper surface side of at least a part of the heater wire laid in the small frame area. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a cooking device having a configuration that allows cooking to be performed efficiently using at least a flat heater as a cooking means. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing the appearance of a cooking device according to an embodiment of the present invention; [Figure 2] FIG. 1 is a perspective view showing a state in which the door of the cooking device according to the present embodiment is open; [Figure 3] FIG. 1 is a perspective view showing a state in which an outer cover of the cooking device according to the present embodiment is removed; [Figure 4] FIG. 1 is an exploded perspective view of a flat heater unit in a cooking device according to an embodiment of the present invention; [Figure 5] FIG. 1 is a diagram showing an upper plate of a heating chamber of a flat heater unit in a cooking device according to an embodiment of the present invention; [Figure 6] 1 is an exploded schematic view showing a flat heater in a cooking device according to an embodiment of the present invention; [Figure 7] FIG. 1 is a plan view showing the vicinity of the upper surface mica of the outer heater in the heating cooker of the present embodiment. [Figure 8] FIG. 10 is a partial plan view of the details of the frame of the outer heater in the cooking device of the present embodiment. [Figure 9] 1 is a plan view of a flat heater in a cooking device according to an embodiment of the present invention; [Figure 10] 1 is a rear view of a flat heater in a cooking device according to an embodiment of the present invention; [Figure 11] A circuit diagram for controlling the cooking means in the cooking device of this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] A cooking device according to a first aspect of the present invention includes: A heating chamber for heating food to be cooked; A cooking device comprising an inner heater disposed on a ceiling wall of a heating chamber and a flat heater constituting a heat source by an outer heater surrounding the inner heater, The outer heater is configured by winding a heater wire around an outer mica, and the inner heater is configured by winding a heater wire around an inner mica, The outer mica has a thick frame portion and a thin frame portion, A heater wire is laid substantially linearly along the longitudinal direction of the frame detail, The cooking device of the first aspect further includes upper mica that covers the upper surface of at least a portion of the heater wires laid in the narrow frame area. In the cooking device of the first aspect configured in this manner, the heater wires are less likely to come into contact with each other, and the heating efficiency of the outer heater can be improved.

[0012] A second aspect of the heating cooker according to the present invention may be configured such that a plurality of heater wires are laid in a substantially straight line along the longitudinal direction of the frame detail in the first aspect, and the plurality of heater wires are spaced apart by the upper mica.

[0013] A cooking device according to a third aspect of the present invention may be configured such that the heater wire laid in a substantially straight line along the longitudinal direction of the frame fine part in the first or second aspect and a part of the heater wire wound around the inner mica are arranged substantially parallel to and close to each other, and the respective heater wires are spaced apart by the frame fine part.

[0014] Hereinafter, as an embodiment of the cooking device of the present invention, a cooking device using at least a flat heater as a cooking means will be described with reference to the accompanying drawings. Note that the cooking device of the present invention is not limited to the cooking device configuration described in the following embodiment, but includes cooking device configurations equivalent to the technical ideas described in the following embodiment. The embodiment described below shows an example of the present invention, and the configurations, functions, operations, etc. shown in the embodiment are illustrative and do not limit the present invention. Among the components in the following embodiment, components not described in the independent claims representing the highest concept will be described as optional components.

[0015] (Embodiment 1) Hereinafter, a cooking device according to the present embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a perspective view showing the appearance of the cooking device according to the present embodiment. Fig. 2 is a perspective view showing the cooking device according to the present embodiment of Fig. 1. 1 is a perspective view showing the cooking device with the door open. FIG.

[0016] As shown in Figures 1 and 2, the cooking appliance is configured so that the front opening of a heating chamber 4 provided inside a main body 1 can be opened and closed by a door 2. A handle 3 is provided at the upper end of the door 2, and a user grasps the handle 3 to rotate the door 2, thereby opening and closing the front opening of the heating chamber 4 in an up-and-down manner. The interior of the heating chamber 4 is substantially sealed when the door 2 is closed, and food to be heated, which is placed inside the heating chamber 4, is heated and cooked in a substantially sealed state.

[0017] As shown in Fig. 1, on the front of the cooking appliance, a setting unit 5, which is a dial-like knob for setting various cooking conditions such as cooking temperature and cooking time, is provided on an upward-opening door 2. The setting unit 5 provided on the front of the cooking appliance also has a display unit that displays various cooking conditions and the heating status during cooking.

[0018] In addition to the flat heater, the cooking means in the cooking appliance of this embodiment includes a microwave heating unit that irradiates microwaves to heat food. Alternatively, a steam heating unit that heats food with steam and a hot air circulation unit that circulates hot air inside the heating chamber 4 to heat food may be used. The microwave heating unit has an antenna that radiates microwaves mounted under the bottom wall of the heating chamber 4, and the directional antenna radiates microwaves in a desired direction inside the heating chamber 4. When a steam heating unit is provided, the cooking appliance has a water tank inside the main body 1, and water from the water tank is heated to a high temperature by a boiler steam heater, generating steam that is sprayed intensively inside the heating chamber 4. When a hot air circulation unit is provided, a rear heater mounted on the rear side of the heating chamber 4 heats air drawn in from the heating chamber 4, and hot air is supplied into the heating chamber 4.

[0019] The cooker of this embodiment is provided with multiple cooking means, and the appropriate cooking means is selected by the user selecting the desired cooking means or the cooking contents. The user places the food to be cooked in the heating chamber 4 of the cooker, closes the door 2, sets the cooking means and cooking contents in the setting unit 5, and presses the start button to start the cooking operation.

[0020] As shown in Fig. 2, the cooking device of this embodiment is configured so that a heating dish 6 on which an object to be heated is placed can be stored inside the heating chamber 4. The heating dish 6 can be placed on the upper, middle, or lower level inside the heating chamber 4, and steps that allow the heating dish 6 to slide and support the heating dish 6 are formed on both side walls of the heating chamber 4. A heating element (not shown) is embedded in the placement surface of the heating dish 6. The heating element absorbs microwaves and generates heat, and ferrite or the like is used for the heating element.

[0021] In this embodiment, an example is described in which ferrite is embedded in the heating dish 6 as the heating element, but the heating element can be anything that absorbs microwaves and generates heat, and the heating element can also be configured by applying it to the back surface of the heating dish. Furthermore, the main material of the heating dish 6 can be anything that has good thermal conductivity, and it can be configured of metal or ceramic.

[0022] In addition, in this embodiment, the heating dish 6 is described as being supported by a step on the side wall of the heating chamber 4, but it may also be suspended from the ceiling wall, or may be provided with feet that protrude downward on the heating dish 6 and placed on the bottom wall of the heating chamber 4.

[0023] An antenna (not shown) that radiates microwaves into the heating chamber 4 is disposed directly below the approximate center of the bottom wall of the heating chamber 4. The antenna in this embodiment has directivity in the radiating direction of the microwaves and is configured to radiate circularly polarized waves directly above the antenna. Therefore, the antenna in this embodiment is provided with a rotation mechanism so that microwaves are uniformly radiated inside the heating chamber 4, and the antenna's radiation port is configured to rotate, and the antenna is also configured to radiate circularly polarized waves to the heating element of the heating plate 6 placed directly above the antenna, thereby causing dielectric heating.

[0024] The bottom wall of the heating chamber 4 is made of a material that transmits microwaves from the antenna. The other walls of the heating chamber 4, including the side, back, and ceiling walls, are made of steel or aluminum-plated stainless steel (SUS). Each wall may also be coated with a non-stick coating layer, such as a fluororesin or silicone resin. This coating layer prevents the adhesion of oils, grease, and other contaminants that splash during cooking, and even if they do, makes them easy to wipe off. Furthermore, each wall of the heating chamber 4 may be coated with a self-cleaning coating layer that automatically decomposes oils and grease splashed during cooking and cleans itself when heated during cooking. Examples of methods for imparting self-cleaning properties to the coating layer include incorporating manganese oxide-based catalyst species that promote oxidative decomposition into the coating layer, or adding platinum, which exhibits significant effects on oxidative decomposition at low temperatures, or palladium, which is highly active in the medium- to high-temperature range. Adding cerium, which has an adsorption effect, may also be used.

[0025] As described above, the object to be heated (food) placed on the heating plate 6 stored inside the heating chamber 4 is heated and cooked by the heating plate 6, which has reached a high temperature due to the heat of the heating element that is dielectrically heated by microwaves.In this embodiment, however, the top surface of the object to be heated (food) placed on the heating plate 6 is heated by a flat heater unit 8 provided on the upper part of the ceiling wall of the heating chamber 4.

[0026] FIG. 3 is a perspective view showing the main body 1 of the cooking device of this embodiment with the outer cover removed. As shown in FIG. 3, a flat heater unit 8 is provided on the ceiling side of the main body 1 of the cooking device, i.e., in the portion including the ceiling wall of the heating chamber 4. As shown in FIG. 3, the upper portion of the heating chamber 4 of the cooking device is configured with the flat heater unit 8. An internal temperature detection unit 9, such as a thermistor, is provided in the right rear corner of the heating chamber 4 as an internal temperature detection means for detecting the internal temperature inside the heating chamber 4. Internal temperature information detected by the internal temperature detection unit 9 is transmitted to the control unit 7 (see FIG. 11 ), which will be described later, and is used to control various cooking operations. Note that although the thermistor is provided in the right rear corner of the heating chamber 4, it may be provided anywhere inside the heating chamber 4 where it can detect the internal temperature, such as the left rear corner, the right front corner, or the left front corner.

[0027] [Flat heater unit] FIG. 4 is an exploded perspective view of the planar heater unit 8. As shown in FIG. 4, the planar heater unit 8 includes, from the bottom of FIG. 4, a heating chamber top plate 10 constituting the ceiling wall of the heating chamber 4, a planar heater 11 in close contact with the upper surface of the heating chamber top plate 10, and a first insulating material 13 blocking upward heat conduction from the planar heater 11. The planar heater unit 8 also includes an insulating sheet 15 that electrically insulates the terminal portion 24 of the planar heater 11 and a heat shield plate 16 that blocks heat transfer from the planar heater unit 8 to the outer cover of the main body 1. As described above, the planar heater unit 8 has a stacked assembly structure, and each component can be replaced during maintenance, improving maintainability. Furthermore, the planar heater unit 8 includes a heater temperature detector 18, which is a heater temperature detection means for detecting the temperature of the heating region directly heated by the planar heater 11. Each component of the planar heater unit 8 is described in detail below.

[0028] [Heating chamber top plate] Fig. 5 is a diagram showing the heating chamber upper plate 10 that constitutes the ceiling wall of the heating chamber 4 in the flat heater unit 8. In Fig. 6, (a) is a plan view of the heating chamber upper plate 10, (b) is an end view of the heating chamber upper plate 10 shown in (a) taken along the line (b)-(b), and (c) is an end view of the heating chamber upper plate 10 shown in (a) taken along the line (c)-(c).

[0029] The heating chamber upper plate 10 constitutes the ceiling wall of the heating chamber 4, and the central portion of the heating chamber upper plate 10, excluding the outer periphery, has a substantially square shape (10a) in a plan view. This square shape has a curved shape with a concave surface on the heating chamber side (underside), which forms the heat-generating region 10a to which the planar heater 11 is closely attached. The heating chamber 4 of this embodiment has a rectangular parallelepiped shape in a front view, with the width and depth directions longer than the height direction, and the heat-generating region 10a covers substantially the entire ceiling wall of the heating chamber 4. The rectangular planar heater 11, which corresponds to the shape of the heating chamber 4, is attached over the entire surface of the curved heat-generating region 10a in close contact with it. Therefore, substantially the entire surface of the heating chamber upper plate 10, which constitutes the ceiling wall of the heating chamber 4, becomes a heat-generating element to be heated by the planar heater 11.

[0030] As shown in the end view of Figure 5(b), the cross section of the heat generation area 10a in the heating chamber upper plate 10 in the horizontal direction (left and right direction in Figure 5(a)) is composed of a curve. Similarly, as shown in the end view of Figure 5(c), the cross section of the heat generation area 10a in the heating chamber upper plate 10 in the vertical direction (up and down direction in Figure 5(a)) is also composed of a curve. Therefore, the heat generation area 10a in the heating chamber upper plate 10 has a three-dimensional curved surface with a concave surface on the heating chamber side.

[0031] As shown in the plan view of Figure 5(a), the heating chamber upper plate 10 has a heat generating region 10a to which the planar heater 11 is closely attached, which has a plurality of regular hexagonal (honeycomb-shaped) regions (honeycomb regions) 10b. In this embodiment, the boundaries of the honeycomb regions 10b in the heating chamber upper plate 10 are formed by grooves that protrude toward the heating chamber, and each honeycomb region 10b has substantially the same area. The heating chamber upper plate 10 configured in this manner is formed by press working.

[0032] As described above, the heating region 10a of the heating chamber top plate 10 is formed with multiple honeycomb regions 10b. Therefore, the heating region 10a expands due to the heat of the planar heater 11 and contracts when the planar heater 11 is turned off. The resulting expansion / contraction deformation force in all directions can be absorbed within each honeycomb region 10b. The heating region 10a is heated by the closely spaced planar heater 11, but the entire surface of the heating region 10a is not uniformly heated by the planar heater 11, resulting in uneven heat distribution in the heating region 10a. Therefore, the expansion / contraction deformation force in the heating region 10a may vary in magnitude in each region. If the heating chamber top plate, which serves as the ceiling wall of the heating chamber 4, were flat and lacked a region capable of absorbing the expansion / contraction deformation force, the ceiling wall would be locally heated, deforming and distorting unevenly. This would create a gap between the heating chamber top plate and the planar heater, making it difficult for heat from the planar heater to be transferred.

[0033] In the cooking device of this embodiment, multiple regions (honeycomb regions) 10b separated by grooves are formed in the heat generation region 10a of the heating chamber upper plate 10. Therefore, the deformation force of expansion / contraction is dispersed and absorbed by each of these honeycomb regions, and the heat generation region 10a of the ceiling wall does not deform or distort locally, and the curved shape with a concave surface on the heating chamber side becomes smoothly raised overall. As a result, the heat generation region 10a maintains close contact with the planar heater 11, allowing it to efficiently and reliably receive heat from the planar heater 11.

[0034] As described above, in this embodiment, the heat generating region 10a of the heating chamber upper plate 10 is prevented from being locally deformed, and the heat generating region 10a maintains the same shape as a whole. The lifting structure ensures that the planar heater 11 is kept in close contact with the heat generating region 10a.

[0035] In this embodiment, the heating region 10a in the heating chamber upper plate 10 is described as being divided into a plurality of regular hexagonal (honeycomb) honeycomb regions 10b, but the honeycomb regions 10b are not limited to a honeycomb shape as long as they are composed of a plurality of regions that can distribute and absorb deformation forces due to local expansion / contraction in the heating region 10a. The plurality of regions that absorb deformation forces due to expansion / contraction can also be polygonal regions such as triangular or rectangular regions, or regions composed of curved lines.

[0036] In this embodiment, the heating chamber top plate 10 is made of steel or aluminum-plated stainless steel (SUS). A black film made of, for example, silicone resin is formed on both sides of the heating chamber top plate 10. By forming this black film on the surface facing the flat heater, heat from the flat heater 11 can be efficiently absorbed. In this embodiment, a self-cleaning coating layer is formed on the heating chamber side of the heating chamber top plate 10, which automatically cleans itself by breaking down grease and oil scattered during cooking. The method for forming the self-cleaning coating layer has been described above, so it will not be repeated here. In this embodiment, a self-cleaning coating layer is also formed on both side walls and the back wall of the heating chamber 4.

[0037] [Flat heater] FIG. 6 is an exploded schematic diagram showing a planar heater 11 mounted in close contact with the heat generating area 10a of the heating chamber upper plate 10. As shown in FIG. 6, an outer heater 21 and an inner heater 20 are disposed between two mica plates, an upper insulating material 22 and a lower insulating material 23, and the position of side P of the outer heater 21 corresponds to the position of side P of the upper insulating material 22 and the lower insulating material 23. The heater 25, which is the heat source of the planar heater 11, is divided into an inner heater (inner heater) 20 and an outer heater (outer heater) 21. The inner heater 20 and the outer heater 21 are disposed substantially on the same plane, with the outer heater 21 disposed to surround the inner heater 20, and each is driven and controlled independently.

[0038] The inner heater 20 is configured to be approximately rectangular, the outer heater is configured to be approximately square, and the outer heater 21 is arranged to surround the inner heater 20, so the outer heater is configured to be composed of a thick frame portion 21d and a thin frame portion 21c. In this embodiment, the inner heater 20 is configured to be steplessly variably controlled within a range of, for example, 300 W to 900 W, and the outer heater 21 is configured to be on / off controlled at, for example, 700 W.

[0039] The inner heater 20 and the outer heater 21 are formed by winding a heater wire 20b and a heater wire 21b around an insulating plate of inner mica 20a and outer mica 21a, respectively, and by increasing the heater output from the conventional 650 W to 900 W, the heater output per unit area is increased by 1.6 times. In this embodiment, for example, 3.0 W / cm 2 In this embodiment, a belt-shaped heater wire having a thickness of 0.144 mm is used as the heater wire for the inner heater 20, and a belt-shaped heater wire having a thickness of 0.10 mm is used as the heater wire for the outer heater 21. By winding the heater wire at a high density, the temperature rise of the heating chamber upper plate 10 can be made uniform.

[0040] Two heater wires 21b1 are also laid in a substantially straight line along the longitudinal direction of the frame portion 21c of the outer heater 21. By laying a plurality of heater wires 21b1 in the frame portion 21c in this way, it is possible to heat from the vicinity of the center of the heating chamber 4 to the end of the heating chamber 4, which is far from the center, in a plan view of the heating chamber 4. For example, when two slices of bread are placed side by side in the heating chamber 4, the heating chamber 4 can be heated. In some cases, the edges of the bread can be heated sufficiently.

[0041] The detailed frame section 21c is made up of a plurality of mica particles, and a plurality of heater wires 21b1 are laid on the lower mica particles 21a2. The heater wires 21b1 are sandwiched between the lower mica particles 21a2 and the upper mica particles 21a1 located near the center of the detailed frame section 21c.

[0042] 7, slits 40 are provided at both ends of the upper mica 21a1 for fixing the heater wires 21b1, and by passing the heater wires 21b1 through the slits 40 at both ends and arranging them below the upper mica 21a1 and above the lower mica 21a2, the two heater wires 21b1 are spaced apart, preventing them from coming into contact and causing a short circuit. Note that the configuration is not limited to the slits 40, and instead, restricting ribs may be provided on the upper mica 21a1 or the lower mica 21a2 to space the two heater wires 21b1 apart, or the two heater wires 21b1 may be glued to the upper mica 21a1 or the lower mica 21a2.

[0043] The relationship between the heater wires 21b1 and the mica will be described with reference to Figure 8. The multiple heater wires 21b1 are spaced apart below the upper mica 21a1 and above the lower mica 21a2 in the range Q1. Furthermore, the multiple heater wires 21b1 are spaced apart above the lower mica 21a2 in the range R, and the upper side of the heater wires 21b1 is not covered by the upper mica 21a1. Furthermore, the multiple heater wires 21b1 are spaced apart below the thick frame portion mica 21a3 of the thick frame portion 21d and above the lower mica 21a2 in the range Q2. This configuration separates the two heater wires 21b1 from each other, preventing them from coming into contact and causing a short circuit. The same effect can be achieved whether there is only one heater wire 21b1 or two or more heater wires 21b1.

[0044] 6, in the inner heater 20, the heater wire 20b1, which is a part of the heater wires of the outer heater, is arranged adjacent to, substantially parallel to, and substantially linearly adjacent to the heater wire 21b1 of the outer heater arranged in the frame thin section 21c. This allows the heater wire 20b1 to be spaced apart from the heater wire 21b1 of the outer heater arranged in the frame thin section 21c, thereby preventing the heater wire 21b1 from coming into contact with the heater wire 20b1 and causing a short circuit. Furthermore, since the heater wire 20b1 and the heater wire 21b1 can be spaced apart by an appropriate distance, the heated object, such as bread, can be appropriately heated without reducing the heater efficiency. The same effect can be achieved whether there is only one heater wire 21b1 or two or more heater wires.

[0045] As shown in Fig. 6, the planar heater 11 is formed by sandwiching heater 25, which is composed of inner heater 20 and outer heater 21 as a single heat source, between two mica plates, upper insulating material 22 and lower insulating material 23. Fig. 9 is a plan view of the planar heater 11, showing upper insulating material 22. Fig. 10 is a back view of the planar heater 11, showing lower insulating material 23.

[0046] 9 and 10, in the upper insulating material 22 and the lower insulating material 23, a part of the area where the heater wires of the inner heater 20 and the outer heater 21 are sandwiched is separated by slits 22a and 23a. Therefore, in the areas of the upper insulating material 22 and the lower insulating material 23 heated by the heater wires of the inner heater 20 and the outer heater 21, respectively, heat transfer from the other area is blocked. The effect of separating by the slits 22a and 23a is that when the inner heater 20 and the outer heater 21 are energized simultaneously, they expand together, preventing a loss of adhesion of the heating chamber upper plate 10. The upper insulating material 22 and the lower insulating material 23 sandwiching the heater 25 are each formed with openings 22b, 23b into which the presser plate locking portion 10c provided on the heating chamber upper plate 10 is inserted. The flat heater 11 has a terminal portion 24, and terminals connected to the heater wires of the inner heater 20 and the outer heater 21 are provided on the terminal portion 24.

[0047] [First insulation material] As shown in Fig. 4, a first insulating material 13 is disposed so as to cover the planar heater 11. The first insulating material 13 has the function of blocking heat from the upper surface of the planar heater 11, and is formed of, for example, glass wool. The first insulating material 13 has a shape that can cover at least the entire heat generating region 10a of the heating chamber upper plate 10, has a substantially uniform thickness, and has elasticity (restoring force) at least in the thickness direction.

[0048] As shown in Fig. 4 above, multiple openings are formed in the first insulating material 13. The opening formed in the center of the first insulating material 13 is a locking part opening 13a that houses the presser plate locking part 10c protruding from the heating chamber upper plate 10. The first insulating material 13 also includes a terminal opening 13c through which the heater wire of the planar heater 11 passes.

[0049] [Pressure plate] As shown in Figure 4, the pressing plate 14 attached to the heating chamber upper plate 10 is formed with a curved area 14a having a curve similar to the heat generating area 10a formed with a curved surface on the heating chamber upper plate 10. The pressing plate 14 has the function of pressing the planar heater 11 against the heat generating area 10a of the heating chamber upper plate 10 via the first insulating material 13, and the entire surface of the planar heater 11 is tightly attached to the heat generating area 10a without any gaps.

[0050] Corresponding to the heating chamber upper plate 10 in FIG. 5, the horizontal cross section of the curved region 14a of the presser plate 14 is substantially curved. Similarly, the vertical cross section of the curved region 14a of the presser plate 14 is also substantially curved. Therefore, the curved region 14a of the presser plate 14 has a three-dimensional curved surface with a concave surface on the heating chamber side (lower side). In this embodiment, the curvature of the horizontal curve of the curved region 14a is different from the curvature of the vertical curve of the curved region 14a, and the horizontal curvature is smaller than the vertical curvature. The curvatures of the horizontal and vertical curves may be approximately the same. As described above, the curved region 14a of the presser plate 14 has a curve similar to that of the heat generation region 10a of the heating chamber upper plate 10.

[0051] As shown in Fig. 4, the presser plate 14 is provided with a terminal mounting portion 14e and a heater temperature detection portion 18. The heater temperature detection portion 18 is a portion that detects the temperature of an area that is directly heated by heat from the planar heater 11. A terminal portion 24 having terminals for the inner heater 20 and the outer heater 21 of the planar heater 11 is mounted on the terminal mounting portion 14e. Each terminal of the terminal portion 24 is connected to a power supply unit that is driven and controlled by the control portion 7 of the cooking appliance.

[0052] The heater temperature detection unit 18 is disposed in a heating region (heating space) that is directly heated by the planar heater 11. In this embodiment, the heating region (heating space) is formed directly above the inner heater 20 in the planar heater 11, and is directly heated by the inner heater 20. The heater temperature detection unit 18 detects the temperature of the heating region that is directly heated by the inner heater 20, and therefore the control unit 7 controls the driving of the heat sources of the various cooking means used in the cooking appliance, such as the planar heater 11, based on this heater temperature information and on internal temperature information from the internal temperature detection unit 9 that detects the temperature inside the heating chamber 4.

[0053] [Heating control] In the cooking device of this embodiment, a microwave heating unit is provided as another cooking means in addition to the planar heater unit 8 configured as described above. The microwave heating unit includes a magnetron that generates microwaves and radiates the microwaves generated by the magnetron from an antenna via a waveguide. The antenna that radiates microwaves to the heating chamber 4 is disposed below the bottom wall of the heating chamber 4 and is configured to radiate microwaves such as circularly polarized waves from below toward the heating chamber 4. The antenna is configured to radiate directional microwaves, and can be rotated to uniformly heat the interior of the heating chamber 4.

[0054] Other cooking means in the cooker of this embodiment may include a steam heating unit that intensively injects steam into the heating chamber to cook food, and a hot air circulation unit that circulates hot air inside the heating chamber 4 to cook food. The steam heating unit has a water tank inside the main body 1, and is configured to intensively inject steam generated by heating water from the water tank to a high temperature with a boiler steam heater into the heating chamber 4. The hot air circulation unit is configured to heat air sucked from the heating chamber 4 with a rear heater provided on the rear side of the heating chamber 4, and supply hot air into the heating chamber 4.

[0055] As described above, the cooking means in the cooker of this embodiment are the flat heater unit 8, microwave heating unit, steam heating unit, and hot air circulation unit, and each cooking means is selected according to the cooking contents, and in some cases, multiple cooking times are driven and controlled simultaneously or in combination. Note that in this embodiment, the heating control by the flat heater unit 8 will be mainly described.

[0056] The detection end (not shown) of the heater temperature detection unit 18 is disposed in the heating region (heating space) that is directly heated by the internal heater 20 of the flat heater 11. The heater temperature detection unit 18 detects the temperature of the space that is directly heated by the internal heater 20, and transmits the detected temperature to the control unit 7 (see FIG. 11) as heater temperature information. The control unit 7 controls the heat source and drive source for the heating cooking operation according to the cooking content set by the user, based on the heater temperature information as well as internal temperature information from the internal temperature detection unit 9 that detects the internal temperature of the heating chamber 4.

[0057] In this embodiment, the heater temperature detection unit 18 is configured to detect the temperature of the heating region (heating space) that is directly heated by the inner heater 20, and therefore the control unit 7 can control the temperature in the heating cooking operation by the inner heater 20 based on highly accurate heater temperature information from the heater temperature detection unit 18. In this embodiment, as will be described later, a speed heating operation is performed in which the temperature of the heating chamber 4 is rapidly increased by the inner heater 20, which has a large heater output, and therefore the heater temperature information is effective in this speed heating operation.

[0058] In conventional cooking appliances, the flat heater is turned on and off based on the detected internal temperature so that the internal temperature of the cooking appliance reaches the set temperature. Therefore, in conventional cooking appliances, the flat heater is turned off long before the internal temperature reaches the set temperature, and then the flat heater is turned on and off repeatedly to gradually bring the internal temperature closer to the set temperature. Therefore, it is difficult to accurately set the internal temperature to the set temperature using the flat heater, and it takes time to reach the set temperature.

[0059] In the cooking device of this embodiment, the control unit 7 controls the temperature during cooking based on the heater temperature information and the temperature information inside the chamber from the heater temperature detection unit 18. In particular, the speed increase control is performed by rapidly increasing the temperature of the heating chamber 4 to reach the set temperature in a short time. In the heating operation, control is performed based on heater temperature information indicating the temperature of the heating region heated by the internal heater 20. This allows the control unit 7 to rapidly heat the heating region heated by the internal heater 20 to the set temperature, thereby rapidly raising the temperature inside the heating chamber 4. As will be described later, the internal heater 20 in this embodiment is configured to be able to control the input current to a desired value and to set the heater output to a desired value. Therefore, after the internal temperature reaches the set temperature, the control unit 7 controls the input current to the internal heater 20 based on the internal temperature information and heater temperature information, thereby enabling the internal temperature to be maintained at the set temperature with high accuracy. As a result, the cooking appliance of this embodiment can significantly reduce the time it takes for the internal temperature to reach the set temperature and can accurately maintain the internal temperature at the set temperature for a predetermined period of time.

[0060] [Cooking operation] Fig. 11 is an example of a circuit diagram for controlling the cooking means in the cooker of this embodiment. The heat sources in the cooking means in the cooker of this embodiment include inner heater 20 and outer heater 21 in flat heater unit 8, steam heater 26 in the steam heating unit, back heater 27 in the hot air circulation unit, and magnetron 28 in the microwave heating unit (see Fig. 11). In addition, a circulation fan motor 29 is used in the hot air circulation unit.

[0061] As shown in the circuit diagram of FIG. 11 , the inner heater 20, outer heater 21, steam heater 26, back heater 27, and circulation fan motor 29 are connected to switching elements for on / off control. They are also connected to an inverter circuit as a driving power source for a magnetron, which is a microwave generating means in the microwave heating unit. In this embodiment, a triac 30 is used as a switching element to control the driving of the inner heater 20, and the current input to the inner heater 20 can be continuously and variably controlled to a desired value. The outer heater 21 uses a relay as a switching element that simply switches on and off. While the outer heater 21 in this embodiment is described as using a relay as a switching element that simply switches on and off, it may also be configured to use a triac as a switching element, as with the inner heater 20, and to continuously and variably control the input power.

[0062] Cooking appliances have a predetermined rated power, and power above that rated power cannot be used. The cooking appliance of this embodiment is configured to be able to cook using multiple cooking means, and is controlled by the control unit 7 so that the power consumption of activated heat sources and the like is always kept within the rated power. In particular, the flat heater unit 8 in the cooking appliance of this embodiment is subjected to distinctive control.

[0063] The heater 25 in the planar heater unit 8 comprises an inner heater 20 and an outer heater 21 that form a single heat source, but in this embodiment, the maximum heater output of the inner heater 20 is, for example, 900 W, and the maximum heater output of the outer heater 21 is, for example, 700 W. Therefore, the total maximum heater output of the inner heater 20 and the outer heater 21 exceeds the rated power (1500 W = 15 A (rated current) × 100 V) in a typical home. In the cooking device of this embodiment, as shown in FIG. 11 , the inner heater 20 is configured to be driven and controlled by a triac 30 as a switching element. Therefore, the inner heater 20 can be driven at a heater output that is continuously variable within a range of 300 to 900 W by a control signal input to the triac 30.

[0064] Hereinafter, a specific cooking operation using the cooking means in the cooking device of the present embodiment will be described with reference to examples.

[0065] When using only the flat heater unit 8 to heat and cook the heating chamber 4 with almost the entire ceiling wall as a heating element, for example, the inner heater 20 of the flat heater 11 can be driven and controlled to a heater output of 700 W, and the outer heater 21 can be turned on to provide a heater output of 700 W, thereby allowing the flat heater 11 to heat the heating chamber 4 with a total heater output of 1,400 W.

[0066] When using the flat heater unit 8 and the microwave heating unit to heat and cook the heating chamber 4 with microwaves from the ceiling wall and the underside of the bottom wall, for example, the inner heater 20 of the flat heater 11 is set to a maximum heater output of 900 W, the outer heater 21 is turned off (0 W), and the heating chamber 4 is heated from above with a total heater output of 900 W by the flat heater 11. On the other hand, in a microwave heating unit used as another heating and cooking means, the magnetron 28 etc. can use a power consumption of, for example, 450 W to heat the heating plate 6 stored in the heating chamber 4, and food placed on the heating plate 6 can be cooked.

[0067] As another example, food placed on the heating tray 6 can be cooked with the outer heater 21 off (0 W), the inner heater 20 at a heater output of 430 W, and 550 W consumed by the magnetron 28 and other components of the microwave heating unit. As described above, even when cooking using the flat heater unit 8 and the microwave heating unit, the desired cooking operation can be performed with power consumption equal to or less than the rated power for a typical household (1500 W = 15 A (rated current) × 100 V).

[0068] In the cooking appliance of this embodiment, the use of the planar heater unit 8 and the microwave heating unit enables concentrated heating of the central portion of the heating chamber 4. The planar heater 11 has a heater output of 900 W, up from the conventional 650 W, resulting in a 1.6-fold increase in heater output per unit area. In particular, the inner heater 20 is configured with a higher heater output than the outer heater 21. Therefore, in the configuration of this embodiment, the inner heater 20, which has a high heater output, can rapidly heat the central portion of the ceiling wall of the heating chamber 4, causing the central portion of the ceiling wall to become a heating element, which can then radiate heat intensively toward the central portion of the heating chamber 4. Furthermore, by winding the heater wire at a high density, the temperature rise of the heating chamber upper plate 10 can be made uniform.

[0069] On the other hand, in the configuration of this embodiment, microwaves (circularly polarized waves) can be radiated from the antenna of the microwave heating unit from below the heating chamber 4 in a concentrated manner toward the center of the heating chamber 4. A heating plate 6 on which food to be heated is placed is housed inside the heating chamber 4, and a heating element that absorbs microwaves and generates heat is embedded in the placing surface of this heating plate 6. As a result, the food on the placing surface of the heating plate 6 is heated from below by the heating plate 6 heated by the heating element in the microwave heating unit, and the central portion of the ceiling wall is heated by the flat heater unit 8, and the food is heated in a concentrated manner by receiving heat radiation from this central portion from above. In other words, the cooking appliance of this embodiment is configured to be able to rapidly heat food on the heating plate 6 placed in the heating chamber 4 at high temperatures from above and below.

[0070] As described above, the cooking device of this embodiment is configured to be able to perform cooking efficiently within the rated power using at least the flat heater as a cooking means. The cooking device of this embodiment is configured to be able to rapidly heat the interior of the heating chamber to a desired high heat output and perform cooking quickly using multiple power devices whose total power consumption exceeds the rated power.

[0071] The cooking device of this embodiment is also configured to be able to quickly increase the temperature inside the cooking chamber and at the same time maintain the temperature inside the cooking chamber (the temperature of the upper plate of the cooking chamber) at a constant temperature. The cooking device of this embodiment is configured to be able to accurately set the temperature inside the cooking chamber (the temperature of the upper plate of the cooking chamber) to a set temperature and shorten the time it takes for the temperature inside the cooking chamber to reach the set temperature, thereby achieving a reduction in cooking time. [Industrial Applicability]

[0072] The cooking appliance of the present invention has a configuration that allows the temperature inside the cooking chamber to be quickly raised to a desired temperature, thereby shortening cooking time and making it a cooking appliance with high market value. [Explanation of symbols]

[0073] 1 Main unit 2 doors 3 handle 4 Heating cabinet 5. Settings 6 Heating Plate 7 Control Unit 8 Flat Heater Unit 9. Temperature detection unit inside the cabinet 10 Heating chamber top plate (ceiling wall) 10a Heat generation area 10b Honeycomb region 10c Presser plate locking part 11 Flat Heater 13 First insulation material 14 Presser plate 15 Insulation sheet 16 Heat shield 18 Heater temperature detector (thermistor) 20 Inner heater 21 Outer heater 20a inner mica 21a Outer mica 21a1 Upper mica (frame details mica) 21a2 Lower mica (frame details mica) 21a3 thick frame mica 20b, 20b1, 21b, 21b1 heater wire 21c Frame details 21d Thick frame 22 Upper insulation 23 Lower insulation 24 Terminal section 25 Heater 26 Steam heater 27 Rear heater 28 Magnetron 29 Circulation fan motor 30 Triac 31 Switch 40 Cutout hole

Claims

1. A heating chamber for heating food to be cooked; A cooking device comprising an inner heater disposed on a ceiling wall of a heating chamber and a flat heater constituting a heat source with an outer heater surrounding the inner heater, The outer heater is configured by winding a heater wire around an outer mica, and the inner heater is configured by winding a heater wire around an inner mica, The outer mica has a thick frame portion and a thin frame portion, A heater wire is laid substantially linearly along the longitudinal direction of the frame detail, The cooking device further comprises upper mica covering the upper surface side of at least a part of the heater wire laid in the frame details.

2. 2. The cooking device according to claim 1, wherein a plurality of heater wires are laid substantially linearly along the longitudinal direction of the frame thin portion, and the plurality of heater wires are spaced apart by the upper mica.

3. 3. The cooking device according to claim 1, wherein the heater wire laid in a substantially straight line along the longitudinal direction of the frame fine part and a portion of the heater wire wound around the inner mica are arranged substantially parallel to and adjacent to each other, and the heater wires are spaced apart by the frame fine part.

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