Heating cooker

Abstract

A heating cooker according to an embodiment of the present disclosure includes a heating chamber for housing a heated object and a planar heater. The planar heater is disposed above the heating chamber and has an inner heater and an outer heater surrounding the inner heater. The inner heater has an inner mica and an inner coiled heating wire. The outer heater has a thick frame portion, a thin frame portion, an outer mica disposed on the thick frame portion and the thin frame portion, an outer coiled heating wire disposed on the thick frame portion, and an outer straight heating wire disposed on the thin frame portion. The thin frame portion has at least one outer straight heating wire disposed along a length direction of the thin frame portion and an upper mica covering at least a portion of the at least one outer straight heating wire from above.

Description

Technical Field

[0001] This disclosure relates to a heating cooker that heats food or other objects contained within a heating chamber by means of a flat heater disposed on the top wall of the heating chamber. Background Technology

[0002] Traditionally, microwave ovens and other heating appliances have heating elements such as infrared heaters, microwave heating units, steam heating units, and hot air circulation units.

[0003] The infrared heater unit is configured to heat the object using radiant heat. The microwave heating unit is configured to heat the object using microwaves. The steam heating unit is configured to heat the object using superheated steam. The hot air circulation unit is configured to heat the object using hot air supplied to the interior of the heating chamber.

[0004] The heating element of the heating cooker also includes a structure that heats the interior of the heating chamber directly through a flat heater disposed on the top wall of the heating chamber (see, for example, Patent Documents 1 and 2).

[0005] The heating element of the heating cooker also includes a structure in which the top wall is heated by a planar heater disposed on the upper surface of the top wall of the heating chamber, and the interior of the heating chamber is indirectly heated by the heated top wall (for example, see Patent Document 3).

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 3-103206

[0009] Patent Document 2: Japanese Patent Application Publication No. 2010-54124

[0010] Patent Document 3: Japanese Patent Application Publication No. 2017-161163 Summary of the Invention

[0011] To improve the heating efficiency of the planar heater, heating wires need to be arranged around the entire periphery of the planar heater.

[0012] The purpose of this disclosure is to prevent the heating wires of the flat heaters from contacting each other in a heating cooker equipped with flat heaters and to improve the heating efficiency of the flat heaters.

[0013] One aspect of the heating cooker disclosed herein is a heating cooker having a heating chamber for housing a food to be heated and a flat heater. The flat heater is disposed above the heating chamber and has an inner heater and an outer heater surrounding the inner heater.

[0014] The inner heater has an inner mica and an inner wound heating wire. The outer heater has: a thick frame portion; a thin frame portion; outer mica disposed in the thick frame portion and the thin frame portion; an outer wound heating wire disposed in the thick frame portion; and an outer straight heating wire disposed in the thin frame portion.

[0015] The thin frame portion has at least one outer straight heating wire arranged along the length direction of the thin frame portion and an upper mica covering at least a portion of the at least one outer straight heating wire from above.

[0016] The heating cooker disclosed herein can prevent the heating wires of the flat heater from contacting each other and can improve the heating efficiency of the flat heater. Attached Figure Description

[0017] Figure 1 This is a perspective view showing the appearance of a heating cooker according to an embodiment of the present disclosure.

[0018] Figure 2 This is a perspective view of the heated cooker with the door open according to the embodiment.

[0019] Figure 3 This is a perspective view of the heating cooker in the embodiment with its outer cover removed.

[0020] Figure 4 This is an exploded perspective view of the planar heater unit of the heating cooker according to the embodiment.

[0021] Figure 5 This is a diagram showing the structure of the upper plate of the planar heater unit of the heating cooker according to the embodiment.

[0022] Figure 6 This is an exploded view of the planar heater of a heating cooker, schematically illustrating an embodiment.

[0023] Figure 7 This is a top view near the upper mica of the outer heater of the heating cooker in the embodiment.

[0024] Figure 8 This is a top view of the thin frame portion of the heating cooker as part of the outer heater in the embodiment.

[0025] Figure 9 This is a top view of the planar heater of the heating cooker according to the embodiment.

[0026] Figure 10 This is a bottom view of the planar heater of the heating cooker according to the embodiment.

[0027] Figure 11 This is a circuit block diagram related to the control of the heating cooker in the implementation method. Detailed Implementation

[0028] The heating cooker of the first aspect of this disclosure is a heating cooker having a heating chamber for accommodating a food to be heated and a flat heater. The flat heater is disposed above the heating chamber and has an inner heater and an outer heater surrounding the inner heater.

[0029] The inner heater has an inner mica and an inner wound heating wire. The outer heater has: a thick frame portion; a thin frame portion; outer mica disposed in the thick frame portion and the thin frame portion; an outer wound heating wire disposed in the thick frame portion; and an outer straight heating wire disposed in the thin frame portion.

[0030] The thin frame portion has at least one outer straight heating wire arranged along the length direction of the thin frame portion and an upper mica covering at least a portion of the at least one outer straight heating wire from above.

[0031] The second type of heating cooker disclosed herein, based on the first type, further includes a lower mica covering at least one outer straight heating wire from below. The at least one outer straight heating wire has multiple outer straight heating wires. The multiple outer straight heating wires are arranged separately from each other between the upper and lower mica in the narrow frame portion.

[0032] The third-party heating cooker disclosed herein, based on the first or second method, further includes an inner heater with an inner linear heating wire. Multiple outer linear heating wires are arranged approximately parallel to and near the inner linear heating wire.

[0033] Hereinafter, the heating cooker 100 according to an embodiment of the present disclosure will be described with reference to the accompanying drawings. The X-axis, Y-axis, and Z-axis shown in the following drawings represent the horizontal (left-right direction), depth (front-back direction), and height (vertical direction) of the heating cooker 100, respectively.

[0034] In the following figures, the front and back sides of the heating cooker 100 correspond to the front and rear of the heating cooker 100, respectively. That is, the front of the heating cooker 100 is in the negative direction of the Y-axis, and the rear of the heating cooker 100 is in the positive direction of the Y-axis.

[0035] In the following figures, when viewed from the front, the left and right sides of the heating cooker 100 correspond to the left and right sides of the heating cooker 100, respectively. That is, the right side of the heating cooker 100 is the positive direction of the X-axis, and the left side of the heating cooker 100 is the negative direction of the X-axis.

[0036] Figure 1 This is a perspective view showing the appearance of the heating cooker 100. Figure 2 This is a 3D view of the heated cooker 100 with its door open. (See image below.) Figure 1 and Figure 2As shown, the heating cooker 100 has: a main body 1 having a front opening; a heating chamber 4 disposed inside the main body 1; and a door 2 covering the front opening of the main body 1.

[0037] A handle 3 is provided at the upper end of the door 2. When the user pulls the handle 3, the door 2 opens, exposing the front opening of the heating chamber 4. After the door 2 closes, the food or other items to be heated contained in the heating chamber 4 are heated and cooked.

[0038] The setting unit 5 is located on the front of the heating cooker 100, specifically on the front surface of the main body 1 to the right of the door 2. The setting unit 5 includes a rotary knob for setting various cooking conditions such as cooking temperature and cooking time, and a display unit for displaying various cooking conditions and the heating status during cooking.

[0039] The heating cooker 100 has a flat heater 11 (see reference) Figure 4 The heating element consists of a microwave heating unit (not shown) and a microwave heating unit.

[0040] The microwave heating unit is located below the bottom surface of the heating chamber 4. The microwave heating unit includes a magnetron 28 (see reference). Figure 11 The device includes a waveguide and an antenna. The magnetron 28 is configured to generate microwaves. The waveguide is configured to propagate the microwaves from the magnetron 28 to the antenna. The antenna is configured to radiate the microwaves propagated through the waveguide into the heating chamber 4.

[0041] The antenna is capable of radiating directional microwaves and circularly polarized microwaves. The control unit 7 (see below) is also described later. Figure 11 The antenna can be rotated or stopped by uniformly heating the object placed in the heating chamber 4.

[0042] The heating cooker 100 may also have a steam heating unit as a heating part, which is configured to heat the object being heated by steam.

[0043] The steam heating unit includes a water tank and a boiler (neither shown) disposed within the main body 1. The boiler is heated by a steam heater disposed within it (see reference). Figure 11 The water from the water tank is heated to generate superheated steam. The steam heating unit is configured to heat the object inside the heating chamber 4 by injecting the superheated steam into the heating chamber 4.

[0044] The heating cooker 100 may also have a hot air circulation unit as a heating part, which is configured to circulate hot air in the heating chamber 4 to heat the object being heated.

[0045] The hot air circulation unit includes a rear heater 27 located behind the rear of the heating chamber 4 (see reference). Figure 11), circulating fan (not shown) and circulating fan motor 29 (see reference) Figure 11 When the circulating fan motor is running, air circulates inside the heating chamber 4 and in the space behind the heating chamber 4. The hot air circulation unit is configured to heat the object to be heated in the heating chamber 4 using hot air generated by heating the air through the rear heater 27.

[0046] The user can directly select one of the multiple heating elements, or select any heating element from the multiple heating elements based on the desired cooking content. When the user places the object to be heated in the heating chamber 4 and closes the door 2, the heating element or cooking content is set via the setting unit 5, and the start button is pressed, the heating cooker 100 begins cooking.

[0047] like Figure 2 As shown, the heating cooker 100 detachably houses the heating plate 6 within the heating chamber 4. Specifically, multiple guide rails (not shown) of different heights are provided on the left and right side walls of the heating chamber 4. Each of the multiple guide rails on the left side wall has the same height as a corresponding guide rail on the right side wall. Thus, the heating plate 6 and other cooking plates can be detachably positioned at any of the multiple heights within the heating chamber 4 according to their intended use.

[0048] The heating plate 6 has a heating element (not shown) embedded in its mounting surface. The heating element is made of ferrite or the like and absorbs microwaves when irradiated, thus generating heat. The heating plate 6 uses this heat to heat the object placed on it.

[0049] The heating element can also be made of materials other than ferrite. The heating element can be coated on the back of the heating plate 6. The main material of the heating plate 6 can be any material with excellent thermal conductivity, such as metal or ceramic.

[0050] In this embodiment, the heating plate 6 is supported by a pair of guide rails provided on the left and right side walls of the heating chamber 4. However, the heating plate 6 may also be suspended from the top wall, or it may have downward-protruding feet and be placed on the bottom surface of the heating chamber 4.

[0051] In the microwave heating unit, the antenna is a rotating antenna of a waveguide structure, located approximately below the center of the bottom surface of the heating chamber 4 and driven to rotate by a rotating mechanism (not shown). The antenna has microwave radiation directivity along the length of the waveguide structure and has an opening located at the top of the antenna for generating circularly polarized waves.

[0052] The heating cooker 100 of this embodiment is configured to uniformly radiate microwaves into the heating chamber 4 by rotating the antenna, and to radiate circularly polarized microwaves into the heating plate 6.

[0053] The bottom surface of heating chamber 4 is made of a material that allows microwaves from the antenna to pass through. The side walls, rear wall, and top of heating chamber 4 are made of steel or aluminized steel sheets.

[0054] The heating chamber 4 can have a non-adhesive coating layer, such as fluororesin or silicone resin, on each wall surface. The coating layer inhibits the adhesion of grease, cooking residue, and other dirt that splashes out during cooking, and makes the adhered dirt easy to wipe off.

[0055] Furthermore, the heating chamber 4 may have a covering layer on each wall surface, which has a self-cleaning function that automatically cleans itself by decomposing the oil components that fly out during cooking through heating.

[0056] To enable the capping layer to have self-cleaning properties, catalysts such as manganese oxides that promote oxidative decomposition can be incorporated into the capping layer. Platinum, which exhibits significant effects on oxidative decomposition at low temperatures, or palladium, which is highly active in the medium to high temperature range, can also be added to the capping layer. Cerium, which has adsorption properties, can also be added to the capping layer.

[0057] In this embodiment, the heating cooker 100, in addition to using the heating plate 6 for heating from below, also utilizes a flat heater unit 8 (see reference 8) installed above the top wall of the heating chamber 4. Figure 3 Heating is performed from above on the object being heated.

[0058] Figure 3 This is a 3D view of the heating cooker 100 with its outer cover removed. (See image below.) Figure 3 As shown, in heating chamber 4 (refer to...) Figure 2 A planar heater unit 8 is disposed above the top wall of the top wall.

[0059] The heating cooker 100 includes an indoor temperature detection unit 9. The indoor temperature detection unit 9, for example, is a thermistor, and is disposed, for example, in the upper right corner of the rear wall of the heating chamber 4 to detect the temperature inside the heating chamber 4 (hereinafter referred to as the indoor temperature). The control unit 7, described later (see...) Figure 11 It receives indoor temperature information detected by the indoor temperature detection unit 9 and performs various controls.

[0060] However, this disclosure is not limited to this structure. As long as the indoor temperature can be detected, the indoor temperature detection unit 9 can also be configured in other locations. For example, the indoor temperature detection unit 9 can be configured at any position, such as the upper left corner of the rear wall of the heating chamber 4, or the upper front corner of the right or left side wall of the heating chamber 4.

[0061] [Planar heater unit]

[0062] Figure 4 This is an exploded perspective view of planar heater unit 8. (See diagram below.) Figure 4 As shown, the planar heater unit 8 includes, from bottom to top, an upper plate 10, a planar heater 11, a first heat insulation member 13, a pressing plate 14, an insulating sheet 15, and a heat insulation plate 16.

[0063] That is, the planar heater unit 8 has a stacked assembly structure. Therefore, all components of the planar heater unit 8 can be easily replaced as needed during maintenance. The planar heater unit 8 also includes a heater temperature detection unit 18, which is disposed on the press plate 14 for detecting the temperature of the heating area directly heated by the planar heater 11.

[0064] The insulating sheet 15 electrically insulates the terminal portion 24 of the planar heater 11 from other components. The heat insulation plate 16 blocks heat conduction from the planar heater unit 8 to the outer casing of the main body 1. The other constituent elements of the planar heater unit 8 will be described below.

[0065] [Upper plate of the heating chamber]

[0066] Figure 5 The document includes a top view (a), a front view (b), and a side view (c) showing the structure of the upper plate 10 for the planar heater unit 8.

[0067] The upper plate 10 forms the top wall of the heating chamber 4. For example... Figure 5 As shown in the top view (a), the upper plate 10 has a roughly square-shaped heating area 10a in its central portion when viewed from above. Therefore, as Figure 5 As shown in the front view (b) and side view (c), the heating region 10a has an upwardly convex three-dimensional curved surface shape. In other words, the heating region 10a has a recess on the lower surface of the surface of the heating region 10a on the side of the heating chamber 4. On the other hand, the upper surface of the heating region 10a is in close contact with the planar heater 11.

[0068] The heating chamber 4 has a cuboid shape. The heating area 10a covers almost the entire top wall of the heating chamber 4. The planar heater 11 has a rectangular shape corresponding to the shape of the top wall of the heating chamber 4. The planar heater 11 covers the entire upper surface of the heating area 10a in a manner that is in close contact with the upper surface of the heating area 10a. Therefore, almost the entire surface of the upper plate 10 is heated by the planar heater 11 and becomes the heating element.

[0069] like Figure 5 As shown in the top view (a), the heating region 10a has a plurality of honeycomb regions 10b, each of which is a regular hexagonal shape (honeycomb shape). The boundary between two adjacent honeycomb regions 10b in the heating region 10a is formed by grooves protruding toward the heating chamber 4.

[0070] More precisely, the grooves protruding towards the heating chamber 4 refer to the grooves formed between two parallel, straight embankments that bulge towards the heating chamber 4. Multiple honeycomb regions 10b each have substantially the same area. The upper plate 10 is formed by stamping.

[0071] When the planar heater 11 is working, the heating region 10a expands; when the planar heater 11 is cut off, the heating region 10a contracts. However, the shape of the honeycomb region 10b can absorb stresses in various directions caused by expansion or contraction.

[0072] When the heating region 10a is heated by the planar heater 11, it is difficult to heat the entire surface of the heating region 10a uniformly, resulting in an uneven heat distribution in the heating region 10a. In this case, the stress generated by the expansion or contraction of a certain part of the heating region 10a may have a different magnitude than the stress in other parts of the heating region 10a.

[0073] When the upper plate 10 has a flat shape, it is difficult for it to absorb stress caused by expansion or contraction. Therefore, uneven deformation of the top wall of the heating chamber 4 may create a gap between the upper plate 10 and the planar heater 11. If such a gap occurs, heat from the planar heater 11 is difficult to transfer to the upper plate 10.

[0074] In this embodiment, the upper plate 10 has a plurality of honeycomb regions 10b formed on the heating area 10a by being divided by grooves. Through this shape, the stress of expansion and contraction is dispersed and absorbed by the plurality of honeycomb regions 10b respectively.

[0075] As a result, the heating area 10a does not deform significantly in any localized area, and the upward-convex curved shape rises smoothly overall. With this structure, the heating area 10a can always maintain a close contact with the planar heater 11, and can efficiently receive heat from the planar heater 11.

[0076] Furthermore, in this embodiment, the heating area 10a of the upper plate 10 has multiple honeycomb areas 10b. However, this disclosure is not limited to this structure, as long as the heating area 10a has multiple areas capable of dispersing and absorbing local expansion and contraction stress. For example, the heating area 10a may also have areas of polygonal shapes other than hexagons, such as triangles or quadrilaterals, or areas composed of curves, etc.

[0077] In this embodiment, the upper plate 10 is made of aluminized steel sheet of steel or stainless steel (SUS). A black film, for example made of silicone resin, is formed on both sides of the upper plate 10. If a black film is formed on the side of the upper plate 10 facing the planar heater, the upper plate 10 can efficiently absorb heat from the planar heater 11.

[0078] As described above, a covering layer can also be formed on the lower surface of the upper plate 10, which has a self-cleaning function that automatically cleans itself by breaking down the oil components that scatter during cooking through heating. A self-cleaning covering layer can also be formed on the left and right side walls and the rear wall of the heating chamber 4.

[0079] [Flat surface heater]

[0080] Figure 6 This is an exploded view schematically showing the planar heater 11 mounted on the heating area 10a of the upper plate 10. (See diagram below.) Figure 6 As shown, the planar heater 11 includes an inner heater 20, an outer heater 21, an upper insulating member 22, and a lower insulating member 23.

[0081] The inner heater 20 and the outer heater 21 are held by the upper insulating member 22 and the lower insulating member 23. The inner heater 20 and the outer heater 21 are arranged such that the edge P2 of the outer heater 21 overlaps with the edge P1 of the upper insulating member 22 and the edge P3 of the lower insulating member 23. The edge P2 of the outer heater 21 is the edge provided in the thin frame portion 21c (described later).

[0082] The inner heater 20 and the outer heater 21 constitute the heater 25, which serves as the heat source for the planar heater 11. The inner heater 20 and the outer heater 21 are substantially arranged on the same plane such that the outer heater 21 surrounds the inner heater 20. The control unit 7 described later (see...) Figure 11 The inner heater 20 and the outer heater 21 can be controlled separately.

[0083] The inner heater 20 is generally rectangular, and the outer heater 21 is generally square and surrounds the inner heater 20. Therefore, the outer heater 21 includes two narrow frame portions 21c and two thick frame portions 21d. The narrow frame portions 21c and the thick frame portions 21d are composed of mica as an insulating plate and heating wires. The width (X-direction dimension) of the narrow frame portions 21c is narrower than the width (Y-direction dimension) of the thick frame portions 21d.

[0084] The inner heater 20 includes an inner mica 20a serving as an insulating plate, an inner straight heating wire 20b1, and an inner wound heating wire 20b2. The inner wound heating wire 20b2 is formed by winding a heating wire around the inner mica 20a and is disposed on the inner mica 20a. The inner straight heating wire 20b1 and the inner wound heating wire 20b2 are connected in series and connected to the terminal portion 24.

[0085] The outer heater 21 has an outer mica 21a serving as an insulating plate, an outer straight heating wire 21b1, and an outer wound heating wire 21b2. The outer straight heating wire 21b1 is at least one (two in this embodiment) substantially straight heating wire disposed on the outer mica 21a in the narrow frame portion 21c. The outer wound heating wire 21b2 is formed by winding a heating wire around the outer mica 21a in the thick frame portion 21d and is disposed in the thick frame portion 21d. The outer straight heating wire 21b1 and the outer wound heating wire 21b2 are connected in series and connected to the terminal portion 24.

[0086] The output power of existing planar heaters is 650W. The output power of the planar heater 11 in this embodiment is 900W, which is 1.6 times the output power per unit area of ​​existing planar heaters.

[0087] In this embodiment, the inner heater 20 of the planar heater 11 is, for example, capable of operating at 3.0 W / cm². 2 The upper plate 10 operates at its output power. The inner heater 20 is composed of a strip of heating wire with a thickness of 0.144 mm, and the outer heater 21 is composed of a strip of heating wire with a thickness of 0.10 mm. By forming the inner heater 20 and the outer heater 21 by high-density winding of the heating wire, the temperature of the upper plate 10 can rise uniformly.

[0088] Two outer straight heating wires 21b1 are arranged in the thin frame portion 21c such that they extend along the length direction of the thin frame portion 21c. With this structure, heating can be uniformly distributed from the center of the heating chamber 4 to the ends of the heating chamber 4. As a result, when two loaves of bread are arranged in the heating chamber 4 for baking, they can be baked uniformly from the center to the ends of the two loaves.

[0089] The outer mica 21a has an upper mica 21a1 and a lower mica 21a2 disposed on the thin frame portion 21c, and mica corner portions 21a3 disposed at the four corners of the outer mica 21a. The outer mica 21a also has two outer straight heating wires 21b1 disposed on the lower mica 21a2. The outer straight heating wires 21b1 are held by the lower mica 21a2 and the upper mica 21a1 disposed near the center of the thin frame portion 21c.

[0090] Figure 7 This is a top view showing the area near the upper mica 21a1 of the outer heater 21 in the heating cooker 100. (See image below.) Figure 7 As shown, two cuts 40 are provided at the front and rear ends of the upper mica 21a1. That is, the upper mica 21a1 has a total of four cuts 40.

[0091] Two outer straight heating wires 21b1 are positioned below the upper mica 21a1 and above the lower mica 21a2. The outer straight heating wires 21b1 are respectively inserted between the two cuts 40 at the front end of the upper mica 21a1 and the corresponding cut of the two cuts 40 at the rear end of the upper mica 21a1.

[0092] In this way, by arranging the two outer straight heating wires 21b1 separately from each other, short circuits of the two outer straight heating wires 21b1 can be prevented.

[0093] This disclosure is not limited to this structure. For example, the two outer straight heating wires 21b1 can be separated from each other by limiting ribs provided on the upper mica 21a1 and the lower mica 21a2. Alternatively, the two outer straight heating wires 21b1 can be separated from each other and closely attached to the upper mica 21a1 and the lower mica 21a2.

[0094] Figure 8 This is a top view showing the thin frame portion 21c, which is part of the outer heater 21 of the heating cooker 100. (See attached image) Figure 8 As shown, the thin frame portion 21c is composed of a portion Q1, two portions R, and two portions Q2 arranged along its length direction.

[0095] Part Q1 is disposed at the center of the thin frame portion 21c along its length. Two parts Q2 are disposed at opposite ends of the thin frame portion 21c along its length. One of the two parts R is disposed between one of the two parts Q2 and part Q1, and the other part of the two parts R is disposed between the other part of the two parts Q2 and part Q1.

[0096] The multiple outer linear heating wires 21b1 of the outer heater 21 are arranged at part Q1 below the upper mica 21a1 and above the lower mica 21a2. That is, at part Q1, the multiple outer linear heating wires 21b1 are covered from above by the upper mica 21a1 and from below by the lower mica 21a2.

[0097] Furthermore, multiple outer linear heating wires 21b1 are positioned at a portion R above the lower mica 21a2, while on the other hand, they are not covered by the upper mica 21a1.

[0098] Furthermore, multiple outer straight heating wires 21b1 are positioned at part Q2 below the mica corner 21a3 and above the lower mica 21a2. That is, at part Q2, multiple outer straight heating wires 21b1 are covered from above by the mica corner 21a3 and from below by the lower mica 21a2.

[0099] This structure allows the two outer linear heating wires 21b1 to be separated from each other, preventing them from contacting and short-circuiting. The same effect can be achieved when the outer heater 21 has one or more outer linear heating wires 21b1.

[0100] like Figure 6 As shown, the inner linear heating line 20b1 of the inner heater 20 is at least one generally straight heating line that is generally parallel to and disposed nearby relative to the outer linear heating line 21b1 of the outer heater 21. The inner linear heating line 20b1 is separate from the outer linear heating line 21b1, thus preventing the inner heater 20 from contacting the outer heater 21 and short-circuiting.

[0101] The inner linear heating wire 20b1 and the outer linear heating wire 21b1 are separated by an appropriate distance, thus enabling efficient and proper heating of the food, such as bread. The same effect can be achieved when the outer heater 21 has one or more outer linear heating wires 21b1.

[0102] like Figure 6 As shown, the heater 25 of the planar heater 11, which includes an inner heater 20 and an outer heater 21, is held by an upper insulating member 22 and a lower insulating member 23. Thus, the planar heater 11 functions as a heat source.

[0103] Figure 9 This is a top view of the planar heater 11 as seen from the side of the upper insulating member 22. Figure 10 This is a bottom view of the planar heater 11 as seen from the side of the lower insulating member 23.

[0104] like Figure 9 and Figure 10 As shown, the upper insulating member 22 has a slit 22a provided in the region where the inner wound heating wire 20b2 and the outer wound heating wire 21b2 are opposite. The lower insulating member 23 has a slit 23a provided in the region where the inner wound heating wire 20b2 and the outer wound heating wire 21b2 are opposite.

[0105] Therefore, the heat transfer between the area heated by the inner heater 20 and the area heated by the outer heater 21 is interrupted by the upper insulating member 22. The heat transfer between the area heated by the inner heater 20 and the area heated by the outer heater 21 is interrupted by the lower insulating member 23.

[0106] The slits 22a and 23a serve the following purpose: When the inner heater 20 and the outer heater 21 are operated, the upper insulating member 22 and the lower insulating member 23 expand. However, the slits 22a and 23a absorb the expansion of the upper insulating member 22 and the lower insulating member 23. As a result, the tightness between the planar heater 11 and the upper plate 10 can be maintained.

[0107] Openings 22b and 23b are formed on the upper insulating member 22 and the lower insulating member 23, respectively. The upper plate 10 of the heating chamber 4 has a pressing plate locking part 10c that protrudes upward and inserts into the openings 22b and 23b (see reference). Figure 5 ).

[0108] The planar heater 11 includes a terminal section 24 with multiple terminals. Each terminal of the terminal section 24 is connected to a corresponding heating wire among the inner wound heating wire 20b2, the outer straight heating wire 21b1, and the outer wound heating wire 21b2. The multiple terminals of the terminal section 24 are connected to the power supply of the heating cooker 100, which is controlled by the control unit 7.

[0109] [First heat insulation component]

[0110] like Figure 4 As shown, in the planar heater unit 8, a first heat insulation member 13 is disposed above the planar heater 11 in a manner that covers the planar heater 11. The first heat insulation member 13 blocks heat from rising upwards from the planar heater 11. The first heat insulation member 13 is made of, for example, glass wool. The first heat insulation member 13 has a shape capable of covering at least the heating area 10a of the upper plate 10, a substantially uniform thickness, and elasticity at least in the thickness direction.

[0111] The first heat insulation member 13 has a locking opening 13a and a terminal opening 13c. The locking opening 13a is formed in the center of the first heat insulation member 13 and is connected to the pressing plate locking portion 10c (see reference). Figure 5 ) Engagement. The terminal opening 13c is an opening formed in the portion of the first heat insulation member 13 above the terminal portion 24 to allow the heating wire of the flat heater 11 to pass through.

[0112] [Press plate]

[0113] like Figure 4 As shown, in the planar heater unit 8, the pressing plate 14 has a curved surface region 14a, which has the same curved surface as the heating area 10a formed on the upper plate 10. The pressing plate 14 presses the planar heater 11 against the heating area 10a of the upper plate 10 through the first heat insulation member 13. As a result, the entire surface of the planar heater 11 is in close contact with the heating area 10a without any gap.

[0114] The curved area 14a of the pressing plate 14 has the same upwardly convex three-dimensional curved shape as the heating area 10a of the upper plate 10. In other words, the curved area 14a has a depression on the lower surface of the curved area 14a on the side of the heating chamber 4.

[0115] In this embodiment, the lateral curvature of the curved region 14a is different from the longitudinal curvature of the curved region 14a. Specifically, the lateral curvature is smaller than the longitudinal curvature. However, the lateral and longitudinal curvatures can also be the same. Furthermore, the lateral and longitudinal directions of the curved region 14a are along the X-axis and Y-axis, respectively.

[0116] like Figure 4 As shown, the pressing plate 14 has a terminal mounting portion 14b and a heater temperature detection portion 18. The heater temperature detection portion 18 detects the temperature of the area directly heated by the flat heater 11. The terminal portion 24 of the flat heater 11 is mounted on the terminal mounting portion 14b.

[0117] The heater temperature detection unit 18 is disposed in the heating area (heating space) directly heated by the planar heater 11. In this embodiment, the heating area (heating space) is formed vertically above the inner heater 20 of the planar heater 11, and is configured to be directly heated by the inner heater 20.

[0118] [Heating Control]

[0119] The heating control using the planar heater unit 8 will be described below.

[0120] The heater temperature detection unit 18 is disposed in the heating area (heating space) directly heated by the inner heater 20 of the planar heater 11, and is configured to detect the temperature of the heating area. The heater temperature detection unit 18 sends the detected temperature as heater temperature information to the control unit 7 (see reference). Figure 11 The control unit 7 controls the heating unit based on the heater temperature information and the indoor temperature information from the indoor temperature detection unit 9, according to the cooking content set by the user.

[0121] Existing heating cookers control the on / off state of the flat heater to bring the indoor temperature to the set temperature. Therefore, it is difficult to control the indoor temperature with high precision, and it takes time to reach the set temperature.

[0122] In this embodiment, the control unit 7 performs temperature control during heating and cooking based on heater temperature information and indoor temperature information. In particular, during rapid heating, the control unit 7 controls the heating and cooking based on heater temperature information indicating the temperature of the heating area heated by the inner heater 20. Rapid heating refers to an operation mode that causes the indoor temperature of the heating chamber 4 to rise rapidly and reach the set temperature in a short time.

[0123] As described later, the inner heater 20 can adjust the heater output to a desired value by setting the input current to an arbitrary value. After the indoor temperature reaches the set temperature, the control unit 7 controls the input current to the inner heater 20 based on the indoor temperature information and the heater temperature information.

[0124] As a result, the heating cooker 100 can quickly bring the indoor temperature to the set temperature through rapid heating action, and can maintain the indoor temperature at the set temperature with high precision.

[0125] [Heating and cooking action]

[0126] Figure 11 This is a circuit block diagram related to the control of the heating cooker 100. (Example) Figure 11 As shown, the heating cooker 100 includes a control unit 7, an inner heater 20, an outer heater 21, a steam heater 26, a rear heater 27, a magnetron 28, and a circulating fan motor 29. The control unit 7 is configured to control the inner heater 20, the outer heater 21, the steam heater 26, the rear heater 27, the magnetron 28, and the circulating fan motor 29 respectively.

[0127] The heating cooker 100 also includes an inverter circuit 33. The control unit 7 drives the magnetron 28 via the inverter circuit 33.

[0128] The heating cooker 100 also includes a triac 30 for controlling the inner heater 20. The triac 30 is connected to the inner heater 20 and can steplessly set the input current to the inner heater 20. The control unit 7 causes the triac 30 to set the input current to the inner heater 20 to a desired value.

[0129] The heating cooker 100 also includes a relay 31 for controlling the outer heater 21. The control unit 7 controls the switching of the outer heater 21 by turning the relay 31 on / off. Alternatively, the heating cooker 100 may also include a three-terminal bidirectional thyristor switch element for the outer heater 21, and the control unit 7 may cause the three-terminal bidirectional thyristor switch element to steplessly change the input power of the outer heater 21.

[0130] The heating cooker 100 also includes a relay 32 for controlling the steam heater 26. The control unit 7 controls the switching of the steam heater 26 by turning the relay 32 on and off.

[0131] Typically, a heating cooker has a predetermined rated power. Since the heating cooker 100 has multiple heating elements, the control unit 7 controls each heating element in a way that keeps the overall power consumption within the rated power. In particular, in this embodiment, the planar heater unit 8 is characterized by control.

[0132] As described above, the planar heater unit 8 has a heater 25 comprising an inner heater 20 and an outer heater 21. The maximum heater output of the inner heater 20 is, for example, 900W, and the maximum heater output of the outer heater 21 is, for example, 700W. Therefore, the maximum heater output of the heater 25 is 1600W. However, this value exceeds the rated power (1500W) of a typical household appliance.

[0133] In this embodiment, the three-terminal bidirectional thyristor switching element 30 can steplessly set the heater output of the inner heater 20 within the range of 300W to 900W. The control unit 7 steplessly sets the output power of the inner heater 20 within the range of 300W to 900W in a manner that ensures the heater output of the heater 25 does not exceed the rated power, and performs 700W switching control on the outer heater 21.

[0134] The following describes the specific heating and cooking functions of the heating cooker 100.

[0135] When cooking using only the planar heater unit 8, the control unit 7 sets the heater output of the inner heater 20 to, for example, 700W using the triac switch element 30, and the relay 31 connects the outer heater 21, which has a heater output of 700W. Thus, the heating cooker 100 heats the food inside the heating chamber 4 with a total heater output of 1400W.

[0136] When using the planar heater unit 8 and the microwave heating unit for heating and cooking, the control unit 7, for example, operates the inner heater 20 at its maximum heater output of 900W and disconnects the outer heater 21. Thus, the heating cooker 100 heats the food from above with a total heater output of 900W.

[0137] On the other hand, the control unit 7 sets the power consumption of the magnetron 28, etc., to, for example, 450W. When microwaves are irradiated onto the heating plate 6 housed in the heating chamber 4, the heating cooker 100 uses the heating plate 6 to heat the object from below.

[0138] As another example, the control unit 7 can also disconnect the outer heater 21, make the inner heater 20 operate with a heater output of 430W, and set the power consumption of the magnetron 28, etc., to 550W.

[0139] Thus, when using the planar heater unit 8 and the microwave heating unit for heating and cooking, the heating cooker 100 performs the desired heating and cooking while keeping the power consumption below the rated power.

[0140] Industrial utilization potential

[0141] As described above, this disclosure can be applied to heating cookers with flat heaters.

[0142] Explanation of reference numerals in the attached figures

[0143] 1: Main body; 2: Door; 3: Handle; 4: Heating chamber; 5: Setting unit; 6: Heating plate; 7: Control unit; 8: Flat heater unit; 9: Indoor temperature detection unit; 10: Top plate; 10a: Heating area; 10b: Honeycomb area; 10c: Press plate locking part; 11: Flat heater; 13: First heat insulation element; 13a: Opening for locking part; 13c: Opening for terminal; 14: Press plate; 14a: Curved area; 14b: Terminal mounting part; 15: Insulating sheet; 16: Heat insulation plate; 18: Heater temperature detection unit; 20: Inner heater; 20a: Inner mica; 20b1: Inner straight heating wire; 20b2: Inner wound heating wire; 21: 21a: Outer mica; 21a1: Upper mica; 21a2: Lower mica; 21a3: Mica corner; 21b1: Outer straight heating wire; 21b2: Outer wound heating wire; 21c: Thin frame; 21d: Coarse frame; 22: Upper insulation; 22a: Slit; 22b: Opening; 23: Lower insulation; 23a: Slit; 23b: Opening; 24: Terminal; 25: Heater; 26: Steam heater; 27: Rear heater; 28: Magnetron; 29: Circulating fan motor; 30: Three-terminal bidirectional thyristor switch element; 31, 32: Relay; 33: Inverter circuit; 40: Cutout; 100: Heating cooker.

Claims

1. A heating cooker comprising: a heating chamber configured to contain an object to be heated; and a planar heater disposed above the heating chamber, having an inner heater and an outer heater surrounding the inner heater, wherein, The inner heater has inner mica and inner wound heating wire. The outer heater has: a coarse frame portion; a fine frame portion; an outer mica portion disposed in the coarse frame portion and the fine frame portion; an outer wound heating wire disposed in the coarse frame portion; and an outer straight heating wire disposed in the fine frame portion. The thin frame portion has: a plurality of outer linear heating wires arranged along the length direction of the thin frame portion; and an upper mica that covers at least a portion of the plurality of outer linear heating wires from above, such that the plurality of outer linear heating wires are arranged separately from each other.

2. The heating cooker according to claim 1, wherein, The heating cooker also includes a lower mica panel that covers the plurality of outer linear heating wires from below. The plurality of outer linear heating wires are arranged at the thin frame portion between the upper mica and the lower mica.

3. The heating cooker according to claim 1 or 2, wherein, The inner heater also has an inner linear heating line, and the plurality of outer linear heating lines are generally parallel to and arranged nearby relative to the inner linear heating line.

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