EP2647915B1

EP2647915B1 - Heating cooker

Info

Publication number: EP2647915B1
Application number: EP11844794.5A
Authority: EP
Inventors: Masaki Shibuya; Hiroshi Fukuda; Makoto Nishimura
Original assignee: Panasonic Corp
Current assignee: Panasonic Corp
Priority date: 2010-12-01
Filing date: 2011-11-24
Publication date: 2021-03-24
Anticipated expiration: 2031-11-24
Also published as: JPWO2012073457A1; WO2012073457A1; EP2647915A1; EP2647915A4

Description

Technical Field

The present invention relates to a microwave and resistance heating cooker which heats an object to be heated by using microwave heating and resistance heating.

Background Art

In a heating cooker of this kind, conventionally, a self-cleaning coated intermediate plate is screwed at several positions to the inner wall of a heating chamber (for example, see JP-UM-A-59-034806 ).
In the above-described conventional configuration, however, the microwave emitted from a magnetron is reflected from the side wall of the heating chamber, and goes around into the gap between the inner wall of the heating chamber and the intermediate plate, so that the upper surface of the heating chamber, and the intermediate plate are heated to cause an energy loss, thereby impairing the heating efficiency of the heating cooker.
Even when the size of the gap between the inner wall of the heating chamber and the intermediate plate is to be reduced, it is difficult to form the inner wall of the heating chamber and the intermediate plate to have a complete flat surface, due to manufacturing reasons. During the assembling process, moreover, the members may be easily deformed, and therefore a small gap may inevitably be formed. Consequently, the microwave goes around into the gap.
EP 0 200 100 A2 describes a heat cooking apparatus. The heat cooking apparatus is arranged to install a flat heater at an outside surface of the wall surface of heating chamber for accommodating food material, which is firmly attached with a flat heater composed of flatly configured heating elements with a heat-proof insulator therebetween. Also, by forming a non-metallic layer on the inner surface of the metallic wall surface facing the heating elements, heat from the heater is efficiently and uniformly conducted so as to perform uniform heating and high heat-cooking efficiency.
DE 28 50 236 A1 describes a microwave oven which has a heating chamber with enamel-coated inner surfaces and a feed waveguides connecting the microwave oscillator to the chamber via a hole in the latter. The chamber and feed waveguide are made separately and connected together in the immediate vicinity of the hole in the chamber's wall. The holes in the waveguide and in the chamber are aligned by a plate through whose centre the antenna passes.
US-4,162,380 A describes a waveguide structure for use in a microwave oven wherein a portion of the wall structure defining the oven cavity also forms a portion of the waveguide. The waveguide is formed of a plurality of wall members cooperatively defining a waveguide conduit for delivering microwave energy from a generator through an inlet opening in the oven cavity wall. The several wall members of the waveguide conduit are pressformed and secured together by mechanical fastening structure to provide high accuracy in the waveguide configuration. The conduit wall further includes a mounting flange secured to the cavity wall to provide further precise accurate association of the waveguide conduit with the cavity wall opening. An external paint coating on the cavity wall defines with a mounting flange of the waveguide conduit wall a capacitive seal therebetween.
EP 0 848 578 A2 describes a microwave oven which includes a cooking chamber and an electrical component compartment separated by a side panel having an opening therein to enable microwave energy generated in the electrical component to be transmitted into the cooking chamber and a cover plate attached to the side panel over the opening. The side panel includes an angled portion integrally formed on the periphery of the opening. In one embodiment, the cover plate includes a peripheral sealing member.

SUMMARY OF THE INVENTION

The invention is defined by the subject-matter of independent claims 1 and 9. The dependent claims are directed to advantageous embodiments.

ADVANTAGES OF THE INVENTION

Advantageously, it is provided a highly-efficient heating cooker which can solve the above-discussed conventional problem, and in which the energy loss is small.
Advantageously, the heating cooker is a heating cooker wherein a heating chamber for heating food, a microwave generating unit which supplies a microwave into the heating chamber, and an intermediate plate which prevents contamination from adhering to an inner wall of the heating chamber, and which extends along the inner wall of the heating chamber are disposed, and at least a part of an end portion of the intermediate plate is fixed at a contact pitch of λ/4 or less to the inner wall of the heating chamber.
According to the configuration, even in the case where a small gap exists between the inner wall of the heating chamber and the intermediate plate, when the intermediate plate is fixed at a contact pitch of λ/4 or less, a radio wave cannot enter the gap, and therefore the intermediate plate and the inner wall of the heating chamber do not generate heat, with the result that it is possible to provide a highly-efficient heating cooker in which the energy loss is small.

Effects of the Invention

The heating cooker of the invention can provide a highly-efficient heating cooker in which the intermediate plate and the inner wall of the heating chamber do not generate heat, and the energy loss is small.

Brief Description of the Drawings

[Fig. 1] Fig. 1 is a front sectional view of a heating cooker of Embodiment 1 of the invention.
[Fig. 2] Fig. 2 is a bottom view of an intermediate plate of the heating cooker.
[Fig. 3] Fig. 3 is a sectional view showing the shape of projections of the intermediate plate, as viewed from the front of the heating cooker.
[Fig. 4] Figs. 4A and 4B are a sectional view showing a bead shape of the intermediate plate, as viewed from the front of the heating cooker, and a bottom view of the intermediate plate of the heating cooker.
[Fig. 5] Fig. 5 is a sectional view showing a bead shape on the upper surface of a heating chamber, as viewed from the front of the heating cooker.
[Fig. 6] Fig. 6 is a sectional view showing a folded shape of the intermediate plate, as viewed from the front of the heating cooker.
[Fig. 7] Fig. 7 is a sectional view showing a choke configuration of the intermediate plate, as viewed from the front of the heating cooker.

Mode for Carrying Out the Invention

In a first configuration, a heating chamber for heating food, a microwave generating unit which supplies a microwave into the heating chamber, and an intermediate plate which prevents contamination from adhering to an inner wall of the heating chamber, and which extends along the inner wall of the heating chamber are disposed, and at least a part of an end portion of the intermediate plate is fixed at a contact pitch of λ/4 or less to the inner wall of the heating chamber.
According to the configuration, even in the case where a small gap exists between the inner wall of the heating chamber and the intermediate plate, a radio wave cannot enter the gap, and therefore the intermediate plate and the inner wall of the heating chamber do not generate heat, with the result that it is possible to provide a highly-efficient heating cooker in which the energy loss is small.
In a second configuration, particularly, at least a part of the end portion of the intermediate plate in the first configuration is screwedly fixed to the inner wall of the heating chamber. According to the configuration, the intermediate plate can be surely made in metallic contact with the inner wall of the heating chamber, and, even when a small gap exists between the inner wall of the heating chamber and the intermediate plate, a radio wave cannot enter the gap. Therefore, the intermediate plate and the inner wall of the heating chamber do not generate heat, and it is possible to provide a highly-efficient heating cooker in which the energy loss is small.
In a third configuration, particularly, at least a part of the end portion of the intermediate plate in the first configuration is weldedly fixed to the inner wall of the heating chamber. According to the configuration, the intermediate plate can be made economically and easily in metallic contact with the inner wall of the heating chamber without increasing the number of parts for fixation, and, even when a small gap exists between the inner wall of the heating chamber and the intermediate plate, a radio wave cannot enter the gap. Therefore, the intermediate plate and the inner wall of the heating chamber do not generate heat, and it is possible to provide a highly-efficient heating cooker in which the energy loss is small.
In a fourth configuration, particularly, projections which are pressingly contacted with the intermediate plate or the inner wall of the heating chamber in the first configuration are disposed on at least a part of the intermediate plate or the inner wall of the heating chamber, and along an end portion of the intermediate plate.
According to the configuration, projecting portions can be pressingly contacted simply by fixing the intermediate plate to the inner wall of the heating chamber at several positions. Since the projections can be disposed by a pressing process, the metallic contact can be made economically and easily. Even when a small gap exists between the inner wall of the heating chamber and the intermediate plate, a radio wave cannot enter the gap. Therefore, the intermediate plate and the inner wall of the heating chamber do not generate heat, and it is possible to provide a highly-efficient heating cooker in which the energy loss is small.
In a fifth configuration, a heating chamber for heating food, a microwave generating unit which supplies a microwave into the heating chamber, and an intermediate plate which prevents contamination from adhering to an inner wall of the heating chamber, and which extends along the inner wall of the heating chamber are disposed, and a folded shape is disposed in at least a part along an end portion of the intermediate plate.
According to the configuration, the strength of the end portion of the intermediate plate is improved, and hence deformation does not occur. Furthermore, an edge portion is not formed, and the gap between the end portion and the upper surface of the heating chamber 1 can be set to substantially 0 mm while ensuring that it is safe to touch. The intermediate plate and the inner wall of the heating chamber do not generate heat, and it is possible to provide a highly-efficient heating cooker in which the energy loss is small.
In a sixth configuration, a heating chamber for heating food, a microwave generating unit which supplies a microwave into the heating chamber, and an intermediate plate which prevents contamination from adhering to an inner wall of the heating chamber, and which extends along the inner wall of the heating chamber are disposed, and a bead shape is disposed in at least a part along an end portion of the intermediate plate.
According to the configuration, the strength of the end portion of the intermediate plate is improved economically and easily by forming the bead shape with a pressing process. Therefore, deformation does not occur, and the gap between the end portion and the upper surface of the heating chamber 1 can be set to substantially 0 mm. The intermediate plate and the inner wall of the heating chamber do not generate heat, and it is possible to provide a highly-efficient heating cooker in which the energy loss is small.
In a seventh configuration, a heating chamber for heating food, a microwave generating unit which supplies a microwave into the heating chamber, and an intermediate plate which prevents contamination from adhering to an inner wall of the heating chamber, and which extends along the inner wall of the heating chamber are disposed, and a convex and concave fitting shape is disposed in at least a part along an end portion of the intermediate plate.
According to the configuration, the strength of the end portion of the intermediate plate is improved, and hence deformation does not occur. Therefore, the gap between the end portion and the upper surface of the heating chamber can be set to substantially 0 mm. Because of the spigot-joint configuration having the convex and concave fitting structure, moreover, a radio wave hardly enters the gap. Therefore, the intermediate plate and the inner wall of the heating chamber do not generate heat, and it is possible to provide a highly-efficient heating cooker in which the energy loss is small.
In an eighth configuration, a heating chamber for heating food, a microwave generating unit which supplies a microwave into the heating chamber, and an intermediate plate which prevents contamination from adhering to an inner wall of the heating chamber, and which extends along the inner wall of the heating chamber are disposed, and a choke structure is disposed in at least a part along an end portion of the intermediate plate.
According to the configuration, a radio wave which enters the gap between the intermediate plate and the heating chamber is surely attenuated by the choke structure. Therefore, the intermediate plate and the inner wall of the heating chamber do not generate heat, and it is possible to provide a highly-efficient heating cooker in which the energy loss is small.

(Embodiment 1)

Fig. 1 is a sectional view of an embodiment of the invention, as viewed from the front of a heating cooker.
Referring to Fig. 1, an upper heater 2 and a lower heater 3 are disposed in a heating chamber 1 in which the surface of a steel plate is coated with enamel, and food 5 placed on a wire rack 4 which is configured by combining and welding together rod members of stainless steel is heated while being interposed between the upper heater 2 and the lower heater 3. Corners of the wall surface of the heating chamber 1 are rounded and bent, and the bottom surface is formed into a large arcuate shape.
The wire rack 4 is placed so as to be interposed between a rail A 12 and a rail B 13. In the embodiment, the wall surface is coated with enamel. Alternatively, another refractory coating may be applied. As the material of the wall surface, stainless steel or a PCM steel plate may be used, and, as the wire rack 4, plated steel members or the like may be used.
A magnetron 6 which generates a microwave is horizontally disposed in an upper right portion of the heating chamber 1 so that the microwave and at least one of radiation heat and convection heat of the upper and lower heaters are supplied to enable the food to be heat treated.
An upper-heater thermocouple 7 is disposed on the upper heater 2 so as to be in contact with its surface, and covered by a metal pipe so as not to be affected by the microwave emitted from the magnetron 6, thereby constituting a heater temperature detecting unit for the upper heater 2.
A lower-heater thermocouple 8 is similarly disposed on the surface of the lower heater 3 to constitute a heater temperature detecting unit. A thermistor 9 which is a chamber temperature detecting unit is fixed to the wall surface of the heating chamber 1. The upper-heater thermocouple 7, the lower-heater thermocouple 8, and the thermistor 9 are electrically connected to a controlling unit 10, so that the energizations of the upper heater 2 and the lower heater 3 can be controlled based on their outputs to adjustingly control the heating amount.
The magnetron 6 is coupled to a waveguide 14 in which the internal passage is horizontally formed into an L-like shape. In the vicinity of the horizontal middle of the cylinder block 1, a rotating antenna 11 which functions as a radio wave stirring unit is disposed while being connected to a motor 18. The waveguide 14 includes a conical dome 15 and a power feeding port 17.
The rotating antenna 11 is configured by an antenna portion 11a and a shaft portion 11b. The antenna portion 11a is made of a metal, and formed into an approximately circular plate of a thickness of 1 mm and about 62ϕ. The shaft portion 11b is disposed at a position which is eccentric by about 12 mm with respect to the center of the circular plate.
The side of the shaft portion 11b on the side of the motor 18 is configured by a fluororesin, and that on the side of the antenna portion 11a is configured by a metal. The metal portion is projected by about 11 mm into the waveguide 14, and by 15 mm toward the heating chamber 1 through the power feeding port 17 of the dome 15. A gap of 5 mm or more is ensured with respect to the power feeding port 17.
The magnetron 6, the rotating antenna 11, the waveguide 14, the dome 15, and the power feeding port 17 are disposed above the upper surface of the heating chamber 1. The invention is not limited to this. They may be disposed on the bottom portion or side surface of the heating chamber 1, and oriented in any direction.
Between the upper surface of the heating chamber 1 and the upper heater 2, an intermediate plate 19 which is a steel plate coated with a self-cleaning coating that decomposes oil or the like scattered from a heated object and adhering to the heating chamber 1 into water and carbon dioxide is disposed on the upper surface of the heating chamber 1 except the dome 15.
In the embodiment, the intermediate plate 19 is disposed on the upper surface of the heating chamber 1 to which oil easily adheres. Since oil may adhere also to the side surface of the heating chamber 1, the intermediate plate 19 may be similarly disposed.
In the embodiment, a self-cleaning coated steel plate is used as the intermediate plate. Alternatively, the steel plate may not be self-cleaning coated as far as it can prevent contamination from adhering to the inner wall of the heating chamber.
A cover 16 which is made of mica is disposed on a lower end portion of the dome 15 so that contamination is prevented from adhering to the rotating antenna 11. In order to prevent the upper heater 2 from being directly affected by the microwave, the upper heater is placed while avoiding a place which is immediately below a lower opening of the dome 15. As the cover 16, mica which is a low-loss dielectric material is used. Alternatively, a similar configuration is obtained also by using ceramic or glass. Fig. 2 is a bottom view of the intermediate plate 19.
Referring to Fig. 2, in the intermediate plate 19, end portions of the periphery of the intermediate plate 19, and a portion of the intermediate plate 19 surrounding the dome 15 are fixed at intervals of about 20 mm by screws 25 to the upper surface of the heating chamber 1. Although, in the embodiment, screwing is performed at intervals of about 20 mm, each of the intervals is requested to be λ/4 or less. From the oscillation frequency of the magnetron 6 which is used in the embodiment, λ/4 is equal to about 30 mm.
In the embodiment, screwing is performed. However, it is requested that the intermediate plate 19 and the upper surface of the heating chamber 1 are contacted with each other at intervals of λ/4 or less. Another joining method such as welding, dick-fitting, or caulking may be used.
Hereinafter, the operation and function of the thus configured heating cooker will be described.
When the user selects a microwave heating mode and turns ON a switch, a microwave is emitted from the magnetron 6. The microwave passes through the waveguide 14, and irradiates the rotating antenna 11. The microwave is supplied into the heating chamber 1 while being stirred by the rotating antenna 1 which is rotated by the motor 18. The microwave which is supplied into the heating chamber 1 is absorbed by the food 5, and the food 5 is heated.
When a resistance heating mode is selected and a switch is turned ON, the upper heater 2 and the lower heater 3 are energized to generate heat, and radiation heat is transmitted within the heating chamber 1 to heat the food 5.
In the microwave heating mode, the vicinities of the end portions of the periphery of the intermediate plate 19, and the portion of the intermediate plate 19 surrounding the dome 15 are screwedly fixed at a contact pitch of λ/4 or less to the upper surface of the heating chamber 1, thereby causing the intermediate plate and the inner wall of the heating chamber to be surely made in metallic contact with each other. Even when a small gap exists between the intermediate plate 19 and the upper surface of the heating chamber 1, a radio wave cannot enter the gap. Therefore, the intermediate plate 19 and the upper surface of the heating chamber 1 do not generate heat, and it is possible to provide a highly-efficient heating cooker in which the energy loss is small.
In the embodiment, the whole vicinities of the end portions are fixed at a contact pitch of λ/4 or less. Even in the case where there is a portion where fixation cannot in any way be performed, and only a part is fixed, similar effects are attained at least in the fixed part.
Alternatively, the intermediate plate 19 may be configured as shown in Fig. 3. Fig. 3 is a sectional view showing the shape of the intermediate plate, as viewed from the front of the heating cooker.
Referring to Fig. 3, similarly with the case of the screw holes of Fig. 2, in the vicinities of end portions of the periphery of the intermediate plate 19, and a portion of the intermediate plate 19 surrounding the dome 15, projections 20 are formed at intervals of about 20 mm by a pressing process, and the projections are pressingly contacted with and fixed to the upper surface of the heating chamber 1.
According to the configuration, the end portion of the intermediate plate 19 is easily fixed at a contact pitch of λ/4 or less to the upper surface of the heating chamber 1 without screwing or welding, and, even when a small gap exists between the intermediate plate 19 and the upper surface of the heating chamber 1, a radio wave cannot enter the gap. Therefore, the intermediate plate 19 and the upper surface of the heating chamber 1 do not generate heat, and it is possible to provide a highly-efficient heating cooker in which the energy loss is small.
Although, in the embodiment, the projections 20 are disposed at intervals of about 20 mm, the intervals may be λ/4 or less. From the oscillation frequency of the magnetron 6 which is used in the embodiment, λ/4 is equal to about 30 mm.
Also when the projections 20 are disposed on the side of the upper surface of the heating chamber 1, similar effects are attained. In the embodiment, the projections are disposed on the whole vicinities of the end portions, and subjected to pressing contact. Even in the case where there is a portion where projections cannot in any way be disposed, and projections are allowed to be disposed only in a part, similar effects are attained at least in the part.
Alternatively, the intermediate plate 19 may be configured as shown in Figs. 4A and 4B. Fig. 4A is a sectional view showing the shape of the intermediate plate, as viewed from the front of the heating cooker, and Fig. 4B is a bottom view of the intermediate plate 19. Referring to Figs. 4A and 4B, beads A 21 are formed in the vicinities of the end portions of the periphery of the intermediate plate 19, and the portion of the intermediate plate 19 surrounding the dome 15.
According to the configuration, the strength of the end portion of the intermediate plate 19 is improved, and hence deformation does not occur, and the gap between the end portion and the upper surface of the heating chamber 1 can be set to substantially 0 mm. The intermediate plate 19 and the upper surface of the heating chamber 1 do not generate heat, and it is possible to provide a highly-efficient heating cooker in which the energy loss is small.
Although, in the embodiment, the bead shape is disposed, any shape may attain similar effects as far as the shape is a convex and concave shape which improves the strength of the end portion. In the embodiment, moreover, the bead shape is disposed in the whole vicinities of the end portions. Even in the case where there is a portion where a bead shape cannot in any way be disposed, and a bead shape is disposed only in a part, similar effects are attained at least in the part.
Alternatively, the upper surface of the heating chamber 1 may be configured as shown in Fig. 5. Fig. 5 is a sectional view showing the shape of the intermediate plate, as viewed from the front of the heating cooker. Referring to Fig. 5, beads B 22 are disposed in the upper surface of the heating chamber 1 in the same places so as to be pressingly contacted with the beads A 21.
According to the configuration, the strength of the end portion of the intermediate plate 19 is improved, and hence deformation does not occur, and a radio wave is caused to hardly enter, by the intermediate plate 19 and the upper surface of the heating chamber 1. The intermediate plate 19 and the upper surface of the heating chamber 1 do not generate heat, and it is possible to provide a highly-efficient heating cooker in which the energy loss is small.
Although, in the embodiment, the bead shape is disposed, any shape may attain similar effects as far as a fitting shape formed by a convex and concave shape is configured between the upper surface of the heating chamber 1 and the intermediate plate 19.
The embodiment is configured so that the bead shape is pressingly contacted with the whole vicinities of the end portions. Even in the case where there is a portion where a bead shape cannot in any way be disposed, and a bead shape is allowed to be disposed only in a part, similar effects are attained at least in the part.
Alternatively, the intermediate plate 19 may be configured as shown in Fig. 6. Fig. 6 is a sectional view showing the shape of the intermediate plate, as viewed from the front of the heating cooker. Referring to Fig. 6, folded portions 23 are disposed in the vicinities of end portions of the periphery of the intermediate plate 19, and a portion of the intermediate plate 19 surrounding the dome 15.
According to the configuration, the strength of the end portion of the intermediate plate 19 is improved, and hence deformation does not occur, and the gap between the end portion and the upper surface of the heating chamber 1 can be set to substantially 0 mm. The intermediate plate 19 and the upper surface of the heating chamber 1 do not generate heat, and it is possible to provide a highly-efficient heating cooker in which the energy loss is small.
Although, in the embodiment, the folded portions are disposed in the whole end portions. Even in the case where there is a portion where a folded portion cannot in any way be disposed, and a folded portion is allowed to be disposed only in a part, similar effects are attained at least in the part.
Alternatively, the intermediate plate 19 may be configured as shown in Fig. 7, Fig, 7 is a sectional view showing the shape of the intermediate plate, as viewed from the front of the heating cooker. Referring to Fig. 7, based on the concept of the λ/4 impedance inversion, end portions of the periphery of the intermediate plate 19, and a portion of the intermediate plate 19 surrounding the dome 15 are configured as a choke structure 24 in which a plurality of folds are made.
According to the configuration, a radio wave which enters the gap between the intermediate plate 19 and the upper surface of the heating chamber 1 is attenuated by the choke structure. Therefore, the intermediate plate 19 and the upper surface of the heating chamber 1 do not generate heat, and it is possible to provide a highly-efficient heating cooker in which the energy loss is small.
The choke structure 24 in the embodiment is an example. Similar effects are attained as far as a choke structure which is configured based on the concept of the λ/4 impedance inversion is disposed in the intermediate plate 19 or the upper surface of the heating chamber 1.
Alternatively, a shielding member which is made of an elastic metal is placed in an end portion of one of the intermediate plate 19 and the heating chamber 1, and makes an electrical contact to shield a radio wave. Also in the alternative, similar effects are attained.
Although, in the embodiment, the choke structure is disposed in the whole end portions. Even in the case where there is a portion where a choke structure cannot in any way be disposed, and a choke structure is allowed to be disposed only in a part, similar effects are attained at least in the part.
Although the invention has been described in detail and with reference to the specific embodiment, it is obvious to those skilled in the art that various changes and modifications can be made.

Industrial Applicability

As described above, in the heating cooker of the invention, highly-efficient heating in which the energy loss is small is enabled. Therefore, the heating cooker can be applied to uses such as: a microwave oven, convection/microwave oven, electric oven, or various commercial microwave heating or thawing apparatuses which are cooking equipment using the microwave functions; an industrial heating apparatus such as a drying apparatus; pottery heating; a sintering or biochemical reaction; and the like.

Description of Reference Numerals and Signs

1: heating chamber
5: food
6: magnetron
19: intermediate plate
20: projection
21: bead A
22: bead B
23: folded portion
24: choke structure
25: screw

Claims

A heating cooker, comprising
a heating chamber (1) for heating food (5),
a microwave generating unit (6) which supplies a microwave into the heating chamber (1), a waveguide (14) including a conical dome (15), and an intermediate plate (19) which prevents contamination from adhering to an inner wall of the heating chamber (1), and which extends along the inner wall of the heating chamber (1), wherein
at least a part of an end portion of the intermediate plate (19) is fixed to the inner wall of the heating chamber (1) by a plurality of joining portions, and
the plurality of joining portions are disposed at a contact pitch in which each of intervals between the plurality of joining portions is λ/4 or less;
characterized in that:
the end portions of the periphery of the intermediate plate (19) and a portion of the intermediate plate (19) surrounding the dome (15) are fixed at equal intervals between the plurality of joining portions, wherein the portion surrounding the dome (15) is arranged within the end portions of the periphery of the intermediate plate (19).
The heating cooker according to claim 1, wherein the plurality of joining portions include screws (25).
The heating cooker according to claim 1, wherein the plurality of joining portions include welding portions.
The heating cooker according to claim 1, wherein the plurality of joining portions includes projections (20) which are pressingly contacted with the intermediate plate (19) or the inner wall of the heating chamber (1).
The heating cooker according to claim 1,
wherein a folded shape is disposed in at least a part along an end portion of the intermediate plate (19).
The heating cooker according to claim 1,
wherein a bead shape is disposed in at least a part along an end portion of the intermediate plate (19).
The heating cooker according to claim 1,
wherein a convex and concave fitting shape is disposed in at least a part along an end portion of the intermediate plate (19).
The heating cooker according to any one of claims 1 to 7, wherein the intermediate plate (19) is a steel plate coated with a self-cleaning coating.
A heating cooker, comprising
a heating chamber (1) for heating food (5),
a microwave generating unit (6) which supplies a microwave into the heating chamber (1), and
an intermediate plate (19) which prevents contamination from adhering to an inner wall of the heating chamber (1), and which extends along the inner wall of the heating chamber (1), characterised in that a choke structure (24) is disposed in at least a part along an end portion of the intermediate plate (19).