TECHNICAL FIELD
[0001] The present disclosure relates to a thermal cooking device that thermally cooks food
to be cooked in a heating compartment, and more particularly, to a thermal cooking
device that heats a cooking object with a plane heater provided above a ceiling wall
of the heating compartment.
BACKGROUND ART
[0002] Thermal cooking means of a thermal cooking device include an infrared heater unit
that directly heats food by radiating heat waves, a microwave heating unit that heats
food by microwave irradiation, a steam heating unit that heats food with water vapor,
and a hot-air circulation unit that heats food by circulating hot air in a heating
compartment.
[0003] As another thermal cooking means of the thermal cooking device, there is also a plane
heater that is provided above a ceiling wall of a heating compartment, which has the
shape of a rectangular parallelepiped, to heat the ceiling wall for indirect heating
of an interior of the heating compartment through the ceiling wall (refer to PTLs
1 and 2).
Citation List
Patent Literatures
[0004]
PTL 1: Unexamined Japanese Patent Publication No. H03-103206
PTL 2: Unexamined Japanese Patent Publication No. 2010-054124
SUMMARY OF THE INVENTION
[0006] The thermal cooking device described above is structured to select an appropriate
cooking means in order to perform, according to a dish, optimum thermal cooking of
food to be cooked in the heating compartment. When the thermal cooking device is used
to heat or cook, it is important that the interior of the heating compartment should
reach a preset cooking temperature (preset temperature) within a short period of time
and that this preset temperature should be held constant for a predetermined period
of time in order to make a dish delicious and to shorten a length of cooking time.
[0007] With use of the plane heater as the thermal cooking means that is provided above
the ceiling wall in the thermal cooking device, the ceiling wall is heated, and the
interior of the heating compartment is heated to the preset temperature by heat radiated
by the heated ceiling wall. As such, highly efficient transfer of heat from the plane
heater to the interior of the heating compartment is required. However, the ceiling
wall is caused by the heat of the plane heater to repeatedly experience expansion
and contraction, so that it is difficult to always maintain close contact between
a ceiling wall surface and the plane heater. A clearance (air layer) is thus caused
between the ceiling wall surface and the plane heater, and there is a problem of deteriorated
efficiency of heat transfer from the plane heater to the ceiling wall.
[0008] A heat source (heater wire) of the plane heater is covered by an electrically insulating
member. The heat from the heat source of the plane heater is transmitted to the ceiling
wall through the electrically insulating member, thus heating the ceiling wall, and
the heat of the heated ceiling wall raises an internal temperature of the heating
compartment to the preset temperature. In the conventional thermal cooking device,
the internal compartment temperature is detected by a temperature detecting means,
and based on this detected internal compartment temperature, on and off control of
the plane heater is performed such that the interior of the heating compartment reaches
the preset temperature. In cases where the heating compartment of such a conventional
thermal cooking device is heated by the plane heater until its internal temperature
reaches the preset temperature, the plane heater reaches a higher temperature than
the preset temperature by the time the internal compartment temperature reaches the
preset temperature. In some cases, the temperature of the plane heater may exceed
its heat resisting temperature. As such, safety and reliability are taken into consideration
in the conventional thermal cooking device. The plane heater is once turned off far
ahead of a time when the internal compartment temperature reaches the preset temperature,
and an on and off operation of the plane heater is repeated thereafter to gradually
bring the internal compartment temperature closer to the preset temperature. As described
above, in the conventional thermal cooking device, the plane heater is controlled
based on the detected internal compartment temperature until the internal compartment
temperature reaches the preset temperature, so that the preset temperature is difficult
to reach with high accuracy, and a length of time is required until the preset temperature
is reached.
[0009] In the conventional thermal cooking device, because the control that maintains the
internal compartment temperature at the preset temperature is the repetition of the
simple on and off operation of the plane heater, the internal compartment temperature
rises and falls, thus being difficult to maintain at the constant temperature.
[0010] Rated power is specified for, for example, the thermal cooking device that is intended
for general home use, thus problematically limiting input power. Accordingly, heat
sources provided in the thermal cooking device must be designed within the rated power.
Particularly in cases where the plane heater is used as the thermal cooking means,
the interior of the heating compartment is difficult to rapidly start up with consumption
of desired power for thermal cooking when the other thermal cooking means are taken
into consideration.
[0011] The present disclosure aims to provide a thermal cooking device that is capable of
rapidly raising an internal temperature of a heating compartment to a preset temperature
and maintaining the internal compartment temperature at the preset temperature when
performing thermal cooking using at least a plane heater as a thermal cooking means.
[0012] A thermal cooking device according to one aspect of the present disclosure includes:
a heating compartment in which a cooking object is heated; a plane heater provided
above a ceiling wall of the heating compartment, the plane heater being one heat source
formed of an inner heater disposed right above a central portion of the ceiling wall,
and an outer heater surrounding the inner heater; and a controller that controls the
inner heater and the outer heater of the plane heater. The ceiling wall of the heating
compartment has a three-dimensional curved surface concavely facing the heating compartment.
The plane heater is fixed to make close contact with the ceiling wall throughout its
entire area.
[0013] According to the present disclosure, use of at least the plane heater as a thermal
cooking means enables an internal compartment temperature to reach a preset temperature
within a short period of time and to be held at the preset temperature without fail.
As such, the thermal cooking device that can be provided is capable of performing
thermal cooking that is desired by a user within a short period of time.
BRIEF DESCRIPTION OF DRAWINGS
[0014]
FIG. 1 is an external perspective view of a thermal cooking device according to an
exemplary embodiment of the present disclosure.
FIG. 2 is a perspective view illustrating the thermal cooking device with a door opened
according to the exemplary embodiment.
FIG. 3 is a perspective view illustrating the thermal cooking device with an outer
cover removed according to the exemplary embodiment.
FIG. 4 is a front elevational view illustrating in section an upper portion of the
thermal cooking device according to the exemplary embodiment.
FIG. 5 is an exploded perspective view of a plane heater unit of the thermal cooking
device according to the exemplary embodiment.
FIG. 6A is a plan view of an upper heating compartment plate of the plane heater unit
in the thermal cooking device according to the exemplary embodiment.
FIG. 6B is an end elevational view taken along line 6B-6B of FIG. 6A.
FIG. 6C is an end elevational view taken along line 6C-6C of FIG. 6A.
FIG. 7 is an exploded perspective view of a plane heater in the thermal cooking device
according to the exemplary embodiment.
FIG. 8 is a plan view of a heater in the thermal cooking device according to the exemplary
embodiment.
FIG. 9 is a top plan view of the plane heater in the thermal cooking device according
to the exemplary embodiment.
FIG. 10 is a rear view of the plane heater in the thermal cooking device according
to the exemplary embodiment.
FIG. 11 is a perspective view illustrating the plane heater mounted to the upper heating
compartment plate in the thermal cooking device according to the exemplary embodiment.
FIG. 12A is a plan view of a keep plate in the thermal cooking device according to
the exemplary embodiment.
FIG. 12B is an end elevational view taken along line 12B-12B of FIG. 12A.
FIG. 12C is an end elevational view taken along line 12C-12C of FIG. 12A.
FIG. 13 is a sectional view describing a method of mounting the keep plate to the
upper heating compartment plate of the thermal cooking device according to the exemplary
embodiment.
FIG. 14 is a sectional view illustrating a mounted condition of the keep plate with
respect to the upper heating compartment plate that is highly heated in the thermal
cooking device according to the exemplary embodiment.
FIG. 15 is an enlarged sectional view illustrating a mounted condition of a heater
temperature sensor in the thermal cooking device according to the exemplary embodiment.
FIG. 16 is a perspective view of the plane heater unit of the thermal cooking device
according to the exemplary embodiment.
FIG. 17A is a plan view of the plane heater unit of the thermal cooking device according
to the exemplary embodiment.
FIG. 17B is a sectional view taken along line 17B-17B of FIG. 17A.
FIG. 17C is a sectional view taken along line 17C-17C of FIG. 17A.
FIG. 18 is a circuit diagram for control of thermal cooking means of the thermal cooking
device according to the exemplary embodiment.
FIG. 19 is a perspective view of a heat-generating pan that is used in the thermal
cooking device according to the exemplary embodiment.
FIG. 20 is a plan view of the heat-generating pan shown in FIG. 19.
DESCRIPTION OF EMBODIMENT
[0015] A thermal cooking device according to a first aspect of the present disclosure includes:
a heating compartment in which a cooking object is heated; a plane heater provided
above a ceiling wall of the heating compartment, the plane heater being one heat source
formed of an inner heater disposed right above a central portion of the ceiling wall,
and an outer heater surrounding the inner heater; and a controller that controls the
inner heater and the outer heater of the plane heater. The ceiling wall of the heating
compartment has a three-dimensional curved surface concavely facing the heating compartment.
The plane heater is fixed to make close contact with the ceiling wall throughout its
entire area.
[0016] According to the first aspect, the thermal cooking device thus formed enables, through
use of the plane heater as a thermal cooking means, an internal compartment temperature
(a temperature of an upper plate) to reach a preset temperature within a short period
of time and to be held without fail at the preset temperature.
[0017] In a thermal cooking device according to a second aspect of the present disclosure,
the three-dimensional curved surface of a ceiling wall surface of the heating compartment
of the first aspect may be rectangular when viewed in a plane and may have a longitudinal
curvature and a transverse curvature that are different from each other.
[0018] In the thermal cooking device according to the first aspect of the present disclosure,
the ceiling wall of the heating compartment includes a plurality of areas that each
absorb deformation force resulting from expansion or contraction that is caused by
heat of the plane heater.
[0019] In a thermal cooking device according to a third aspect of the present disclosure,
the ceiling wall of the heating compartment of the first aspect may include a plurality
of areas that each absorb deformation force resulting from expansion or contraction
that is caused by heat of the plane heater, and the plurality of areas may be identical
in shape.
[0020] In a thermal cooking device according to a fourth aspect of the present disclosure,
the ceiling wall of the heating compartment of the first aspect may include a plurality
of polygonal areas that each absorb deformation force resulting from expansion or
contraction that is caused by heat of the plane heater.
[0021] In a thermal cooking device according to a fifth aspect of the present disclosure,
the ceiling wall of the heating compartment of the first aspect may include a plurality
of honeycomb-shaped areas that each absorb deformation force resulting from expansion
or contraction that is caused by heat of the plane heater.
[0022] In a thermal cooking device according to a sixth aspect of the present disclosure,
the plane heater of the first aspect may be held, via a heat insulator, by a keep
plate that is mounted to the ceiling wall to have a movable range and has a three-dimensional
curved surface.
[0023] In a thermal cooking device according to an seventh aspect of the present disclosure,
the keep plate of the seventh aspect may be formed with, in areas respectively facing
the inner heater and the outer heater, pressing parts that project toward the inner
heater and the outer heater, and the pressing parts may press the inner heater and
the outer heater via the heat insulator.
[0024] In a thermal cooking device according to a eighth aspect of the present disclosure,
a total of respective maximum heater outputs of the inner heater and the outer heater
of the first aspect may exceed rated power of the thermal cooking device. The controller
may control power that is input to the inner heater to prevent a total of respective
heater outputs of the inner heater and the outer heater from exceeding the rated power
of the thermal cooking device.
[0025] A thermal cooking device according to a ninth aspect of the present disclosure may
include a heater temperature sensor that detects a temperature of an area that undergoes
direct heating by the inner heater of the first aspect. Based on heater temperature
information detected by the heater temperature sensor, the controller may perform
control that starts up the inner heater to cause the inner heater to reach a temperature
(including its proximity) that is preset for the heating compartment.
[0026] In a thermal cooking device according to a tenth aspect of the present disclosure,
at least a plane-heater-end surface of the ceiling wall of the first aspect's heating
compartment may have a black silicon film.
[0027] In a thermal cooking device according to an eleventh aspect of the present disclosure,
at least the ceiling wall of the first aspect's heating compartment may have a self-cleaning
film at its heating-compartment-end surface.
[0028] With reference to the accompanying drawings, a description is hereinafter provided
of, as an exemplary embodiment of the thermal cooking device of the present disclosure,
a thermal cooking device that uses at least a plane heater as a thermal cooking means.
[0029] The thermal cooking device according to the exemplary embodiment of the present disclosure
is described below with reference to the accompanying drawings. FIG. 1 is an external
perspective view of the thermal cooking device according to the present exemplary
embodiment.
FIG. 2 is a perspective view illustrating the thermal cooking device of FIG. 1 with
a door opened according to the present exemplary embodiment.
[0030] As shown in FIGS. 1 and 2, heating compartment 4 provided inside main body 1 of the
thermal cooking device has a front opening that can be exposed and closed by door
2. Handle 3 is provided at an upper end of door 2. A user holds handle 3 and rotates
door 2, whereby the front opening of heating compartment 4 is exposed or closed upwardly.
As door 2 is closed, an interior of heating compartment 4 is substantially sealed,
so that a cooking object to be heated disposed in heating compartment 4 is thermally
cooked in a substantially sealed condition.
[0031] As shown in FIG. 1, the thermal cooking device is provided with, at its front face
of door 2 that opens upwardly, setting part 5 where various cooking conditions including
a cooking temperature and a length of cooking time are set for thermal cooking. Setting
part 5 provided at the front face of the thermal cooking device has, for example,
a display that displays the various cooking conditions, a heating condition during
thermal cooking, and others.
[0032] Thermal cooking means used in the thermal cooking device according to the present
exemplary embodiment include, in addition to a plane heater, a microwave heating unit
that heats food by microwave irradiation, a steam heating unit that heats food with
water vapor, and a hot-air circulation unit that heats food by circulating hot air
in heating compartment 4. The microwave heating unit is provided with, below a bottom
wall of heating compartment 4, an antenna that radiates microwaves. The antenna has
directivity and radiates the microwaves in a desired direction toward the interior
of heating compartment 4. The steam heating unit has a water tank inside main body
1 and intensively ejects into heating compartment 4 water vapor that is generated
by heating water to a high temperature by means of steam heaters of a boiler. The
hot-air circulation unit sucks air from heating compartment 4, heats the air by means
of a rear heater provided behind heating compartment 4, and supplies the heated air
to the interior of heating compartment 4.
[0033] The thermal cooking device according to the present exemplary embodiment is provided
with the plurality of thermal cooking means. An appropriate thermal cooking means
is selected when the user selects a desired thermal cooking means or a cooking content.
The user places food to be cooked in heating compartment 4 of the thermal cooking
device, closes door 2, sets the thermal cooking means or the cooking content by means
of setting part 5, and presses a start button to start a cooking operation.
[0034] As shown in FIG. 2, heating compartment 4 of the thermal cooking device of the present
exemplary embodiment can accommodate heat-generating pan 6 on which a heating object
is placed. Both side walls of heating compartment 4 are formed with steps that can
slidably support heat-generating pan 6, so that heat-generating pan 6 is disposed
at a top level, a middle level, or a bottom level inside heating compartment 4. A
heat generator (not shown) is embedded at mounting surface 33 of heat-generating pan
6. This heat generator absorbs microwaves to generate heat, and ferrite is used as
an example of the heat generator.
[0035] While the present exemplary embodiment is described using the example in which ferrite
is embedded as the heat generator in heat-generating pan 6, the heat generator may
be anything that absorbs microwaves to generate heat and may be applied to a back
surface of the heat-generating pan. A main material of heat-generating pan 6 may be
anything with excellent heat conduction and may be a metal or ceramic.
[0036] While the present exemplary embodiment is described with heat-generating pan 6 supported
by the steps on the side walls of heating compartment 4, heat-generating pan 6 may
be suspended from a ceiling wall or may be provided with downwardly projecting legs
to be mounted on the bottom wall of heating compartment 4.
[0037] It is to be noted that the antenna (not shown) that radiates microwaves toward the
interior of heating compartment 4 is disposed underneath a substantially central position
of the bottom wall of heating compartment 4. In the present exemplary embodiment,
the antenna has the directivity in the microwave radiating direction and is capable
of radiating circularly polarized waves upwardly of the antenna. As such, the antenna
is provided with a rotary mechanism in the present exemplary embodiment to uniformly
radiate the microwaves toward the interior of the heating compartment 4 with its radiation
port being rotated. In the present exemplary embodiment, the antenna radiates, for
dielectric heating, the circularly polarized waves even toward the heat generator
of heat-generating pan 6 that is disposed right above the antenna.
[0038] The bottom wall of heating compartment 4 is formed of material that transmits the
microwaves from the antenna. A steel or stainless steel (SUS) plate that is plated
with aluminum is used for the other walls of heating compartment 4, that is to say,
the side walls, the rear wall, and the ceiling wall. Each of the walls may be formed
with a non-adhesive film layer of, for example, fluororesin or silicon resin. With
the formation of such a film layer, dirt that is scattered during cooking, such as
oil, fat, or cooking bits, can be prevented from adhering to the film layer, and even
the adhered dirt is wiped off with ease. Each of the walls of heating compartment
4 may be formed with a film layer with a self-cleaning function that effects automatic
cleaning by decomposing the oil and the fat that are scattered during cooking through
heating that is performed for the cooking. An example that may be used as a method
of making the film layer have the self-cleaning function is a method of incorporating
into the film layer a manganese oxide catalyst species or the like that promotes an
oxidative decomposition effect or a method of adding platinum that exhibits a marked
effect in oxidative decomposition at low temperatures or palladium that is highly
active in a medium-to-high temperature range. As another alternative, a method of
adding, for example, cerium that has an absorptive effect may be used.
[0039] While a heating object (food) that is placed on heat-generating pan 6 accommodated
by heating compartment 4 is thermally cooked by heat-generating pan 6 that is highly
heated by the heat of the heat generator undergoing microwave dielectric heating as
described above, an upper surface of the heating object (food) placed on heat-generating
pan 6 is heated, in the present exemplary embodiment, by plane heater unit 8 that
is provided above the ceiling wall of heating compartment 4.
[0040] FIG. 3 is a perspective view illustrating the thermal cooking device with an outer
cover removed from main body 1 according to the present exemplary embodiment. As shown
in FIG. 3, main body 1 of the thermal cooking device is provided with plane heater
unit 8 at its ceiling, namely, in its part including the ceiling wall of heating compartment
4. FIG. 4 is a front elevational view illustrating in section an upper portion of
the thermal cooking device according to the present exemplary embodiment. As shown
in FIG. 4, a part above heating compartment 4 of the thermal cooking device is formed
of plane heater unit 8. Internal compartment temperature sensor 9 such as a thermistor
is provided as an internal compartment temperature detecting means at a right-hand
rear corner of heating compartment 4 to detect an internal temperature of heating
compartment 4. Internal compartment temperature information that is detected by internal
compartment temperature sensor 9 is transmitted to controller 7 (refer to FIG. 18),
which is described later, and is used for control in various thermal cooking operations.
[Plane heater unit]
[0041] FIG. 5 is an exploded perspective view of plane heater unit 8. As shown in FIG. 5,
plane heater unit 8 has, in order from a bottom in FIG. 5, upper heating compartment
plate 10 that forms the ceiling wall of heating compartment 4, plane heater 11 that
is closely fitted to an upper surface of upper heating compartment plate 10, pressing
tools 12 that are formed of mica and serve as stiffening plates, first heat insulator
13 that blocks upward heat transfer from plane heater 11, and keep plate 14 that presses
plate heater 11 against upper heating compartment plate 10 via first heat insulator
13. Plane heater unit 8 is also provided with insulating sheet 15 that electrically
insulates, for example, terminal part 24 (refer to FIG. 16) of plane heater 11, heat
shield plate 16 that blocks transfer of heat of plane heater unit 8 to the outer cover
of main body 1, and second heat insulator 17. Plane heater unit 8 is assembled to
have such a stacked structure, and all the components can be replaced during maintenance,
so that improved maintainability is achieved. Plane heater unit 8 is also provided
with heater temperature sensor 18 that detects, as a heater temperature detecting
means, a temperature of a heating area that is heated directly by plane heater 11.
The components of plane heater unit 8 are detailed below.
[Upper heating compartment plate]
[0042] FIGS. 6A to 6C illustrate plane-heater-unit upper heating compartment plate 10 that
forms the ceiling wall of heating compartment 4 in plane heater unit 8. FIG. 6A is
a plan view of upper heating compartment plate 10. FIG. 6B is an end elevational view
of upper heating compartment plate 10 of FIG. 6A, taken along line 6B-6B. FIG. 6C
is an end elevational view of upper heating compartment plate 10 of FIG. 6A, taken
along line 6C-6C.
[0043] Upper heating compartment plate 10 forms the ceiling wall of heating compartment
4, and its central portion other than its outer peripheral border has a rectangular
form (10a) when viewed in a plane.
This rectangular form has curved surfaces concavely facing the heating compartment
(downward) and is heat-generating area 10a to which plane heater 11 is closely fitted.
In the present exemplary embodiment, heating compartment 4 has the shape of a rectangular
parallelepiped having a long side on its front face side with heat-generating area
10a covering a substantially entire area of the ceiling wall of heating compartment
4. Plane heater 11 is rectangular correspondingly to the shape of heating compartment
4 and is closely fitted to an entire area of heat-generating area 10a having the curved
surfaces. As such, the substantially entire area of upper heating compartment plate
10 that forms the ceiling wall of heating compartment 4 is a heat generator that undergoes
heating by plane heater 11.
[0044] As shown in the end elevational view of FIG. 6B, a longitudinal section (taken along
a left-right line in FIG. 6A) of heat-generating area 10a of upper heating compartment
plate 10 is defined by a curve. As shown in the end elevational view of FIG. 6C, a
transverse section (taken along an up-down line in FIG. 6A) of heat-generating area
10a of upper heating compartment plate 10 is similarly defined by a curve. Thus, heat-generating
area 10a of upper heating compartment plate 10 has the three-dimensional curved surface
concavely facing the heating compartment. In the present exemplary embodiment, a curvature
of the longitudinal curve of heat-generating area 10a differs from a curvature of
the transverse curve of heat-generating area 10a. The longitudinal curvature is greater
than the transverse curvature. Heat-generating area 10a is not limited to this and
may have a longitudinal curvature that is smaller than its transverse curvature.
[0045] In upper heating compartment plate 10, heat-generating area 10a to which plane heater
11 is closely mounted has a plurality of areas (honeycomb areas) 10b each having the
shape of a regular hexagon (honeycomb) as shown in the plan view of FIG. 6A. In upper
heating compartment plate 10 of the present exemplary embodiment, boundaries of honeycomb
areas 10b are formed of respective grooves that project toward the heating compartment,
and honeycomb areas 10b have respective areas that are substantially identical. Upper
heating compartment plate 10 having such a structure is formed by press working.
[0046] As described above, heat-generating area 10a of upper heating compartment plate 10
is formed to have the plurality of honeycomb areas 10b. Heat-generating area 10a expands
with heat of plane heater 11 or contracts when plane heater 11 is in an off condition
with power cut off. However, deformation forces resulting from expansion or contraction
in all directions can be absorbed within honeycomb areas 10b. While heat-generating
area 10a is heated by closely fitted plane heater 11, heat-generating area 10a is
not uniformly heated throughout its entire area by plane heater 11, so that there
is non-uniformity in heat generation distribution of heat-generating area 10a. Accordingly,
the deformation forces resulting from the expansion or the contraction can be of different
magnitudes among the areas of heat-generating area 10a. If the upper heating compartment
plate, which is the ceiling wall of heating compartment 4, had a flat shape with no
areas that can each absorb deformation force resulting from expansion or contraction,
the ceiling wall would undergo localized heating and thus would be deformed and distorted
in a non-uniform manner. A clearance would thus be caused between the upper heating
compartment plate and the plane heater, so that this structure makes it difficult
for heat to be transferred from the plane heater.
[0047] In the thermal cooking device according to the present exemplary embodiment, heat-generating
area 10a of upper heating compartment plate 10 is formed with the plurality of areas
(honeycomb areas) 10b that are divided by the grooves from one another. As such, the
deformation forces resulting from the expansion or the contraction are dispersed among
these honeycomb areas and are absorbed. Heat-generating area 10a of the ceiling wall
does not undergo significant localized deformation and distortion, and its curved
surface concavely facing the heating compartment thus rises smoothly as a whole. As
a result, heat-generating area 10a maintains its close contact with plane heater 11
and thus can receive heat from plane heater 11 with higher efficiency and without
fail.
[0048] As described above, heat-generating area 10a of upper heating compartment plate 10
is prevented from undergoing localized deformation in the present exemplary embodiment
and rises as a whole while maintaining a similar shape as a whole, so that the close
contact between plane heater 11 and heat-generating area 10a is maintained without
fail.
[0049] While upper heating compartment plate 10 of the present exemplary embodiment is described
with heat-generating area 10a being divided into the plurality of honeycomb areas
10b that each have the shape of the regular hexagon (honeycomb), the honeycomb is
not necessarily specified for the shape of area 10b. Heat-generating area 10a may
be formed of any plurality of areas among which localized deformation forces resulting
from expansion or contraction can be dispersed and absorbed. For example, areas each
having the shape of a polygon such as a triangle or a quadrangle or areas formed by
curved lines can absorb deformation forces resulting from expansion or contraction.
[0050] In the present exemplary embodiment, upper heating compartment plate 10 is provided
with, at its substantially central position, keep plate engagement part 10c to which
keep plate 14 (described later) is mounted to play vertically. Keep plate 14 is mounted
to this keep plate engagement part 10c with stepped screw serving as locking tool
19 that is screwed into keep plate engagement part 10c. Upper heating compartment
plate 10 is also provided with a plurality of projecting fasteners 10d to achieve
close mounting of plane heater 11. Fasteners 10d are small pieces projecting upward
from the upper surface of heat-generating area 10a. Heat-generating area 10a has these
bendable plates fixed to its upper surface.
[0051] In the present exemplary embodiment, the steel or stainless steel (SUS) plate that
is plated with aluminum is used for upper heating compartment plate 10. Upper heating
compartment plate 10 is formed with, for example, a black film member made of, for
example, silicon resin at each of its surfaces. With the formation of such a black
film member on the plane-heater-end surface, heat from plane heater 11 can be absorbed
with high efficiency. In the present exemplary embodiment, upper heating compartment
plate 10 is formed with, at its heating-compartment-end surface, the film layer with
the self-cleaning function that effects the automatic cleaning by decomposing oil
and fat that are scattered during cooking through heating that is performed for the
cooking. The method of forming the film layer having the self-cleaning function has
been mentioned above and thus is omitted here. In the present exemplary embodiment,
the film layer having the self-cleaning function is formed even on each of the side
walls as well as on the rear wall of heating compartment 4.
[Plane heater]
[0052] FIG. 7 is an exploded perspective view of plane heater 11 that is closely mounted
to heat-generating area 10a of upper heating compartment plate 10. As shown in FIG.
7, heater 25 that is a heat source in plane heater 11 is divided into inner-side heater
(inner heater) 20 and outer-side heater (outer heater) 21. FIG. 8 is a plan view of
heater 25, which is the heat source formed of inner heater 20 and outer heater 21.
With outer heater 21 surrounding inner heater 20, inner heater 20 and outer heater
21 are disposed substantially on the same plane and are drivingly controlled in a
separate manner. In the present exemplary embodiment, inner heater 20 is variably
controlled in a stepless manner in a range of from 300 W to 900 W, while outer heater
21 undergoes on and off control using 700 W.
[0053] Inner heater 20 and outer heater 21 are each formed by winding of a heater wire around
an insulating plate of mica, and with a heater output of 900 W as opposed to 650 W
in conventional cases, and thus a heater output per unit area is 1.6 times greater.
In the present exemplary embodiment, an (inner-heater) heater output of 3.0 W/cm
2, for example, is possible. It is to be noted that in the present exemplary embodiment,
the heater wire used for inner heater 20 is belt-shaped and 0.144 mm in thickness,
while the heater wire used for outer heater 21 is belt-shaped and 0.10 mm in thickness.
Because the heater wires are densely wound during the formation, upper heating compartment
plate 10 can undergo a more uniform temperature rise.
[0054] As shown in FIG. 7, heater 25 that is formed, as the one heat source, of inner heater
20 and outer heater 21 is held from both sides by two plates of mica, namely, upper
insulator 22 and lower insulator 23. In this way, plane heater 11 is formed. FIG.
9 is a top plan view of plane heater 11, showing upper insulator 22. FIG. 10 is a
rear view of plane heater 11, showing lower insulator 23.
[0055] As shown in FIGS. 9 and 10, upper insulator 22 and lower insulator 23 each have areas
where the respective heater wires of inner heater 20 and outer heater 21 are clamped,
and these areas are divided by slit 22a, 23a. As such, the areas of each of upper
and lower insulators 22 and 23 are respectively heated by the respective heater wires
of inner and outer heaters 20 and 21 with heat transfer being blocked between these
areas. Slit 22a, 23a serving as the division can prevent the close fitting of upper
heating compartment plate 10 from being impaired due to expansion of both inner heater
20 and outer heater 21 that are energized simultaneously. Upper insulator 22 and lower
insulator 23 that clamp heater 25 are each formed with openings 22b, 23b through which
above-mentioned keep plate engagement part 10c and the plurality of fasteners 10d
of upper heating compartment plate 10 are respectively inserted. Plane heater 11 has
terminal part 24. Terminal part 24 is provided with terminals that are connected to
the respective heater wires of inner heater 20 and outer heater 21.
[0056] FIG. 11 is a perspective view illustrating plane heater 11 mounted to the upper surface
of above-mentioned upper heating compartment plate 10. As shown in FIG. 11, plane
heater 11 is closely mounted to curved heat-generating area 10a of upper heating compartment
plate 10. Fasteners 10d formed on upper heating compartment plate 10 are bent to closely
mount plane heater 11 in a predetermined position on heat-generating area 10a. Here
fasteners 10d of upper heating compartment plate 10 are respectively passed through
openings (22b, 23b), which are formed to vertically pass through plane heater 11,
and respective holes in pressing tools 12, which serve as the stiffening plates formed
of mica, and then are bent, whereby plane heater 11 is closely mounted to the upper
surface of heat-generating area 10a. Keep plate engagement part 10c provided at the
central position of upper heating compartment plate 10 is disposed in openings (22b,
23b) that are formed in a center of plane heater 11.
[First heat insulator]
[0057] As shown in FIG. 5, first heat insulator 13 is disposed over plane heater 11. First
heat insulator 13 functions to block off heat from an upper surface of plane heater
11 and is formed of, for example, glass wool. First heat insulator 13 is shaped to
cover at least the entire area of heat-generating area 10a of upper heating compartment
plate 10, has a substantially uniform thickness, and has elasticity (restoring force)
at least thickness-wise.
[0058] As shown in above-mentioned FIG. 5, first heat insulator 13 is formed with a plurality
of openings. The opening formed in a center of first heat insulator 13 is engagement
part opening 13a that receives keep plate engagement part 10c protrusively provided
to upper heating compartment plate 10. Included in first heat insulator 13, fastener
openings 13b respectively receive fasters 10d that are provided to upper heating compartment
plate 10, terminal opening 13c allows passage of the heater wires of plane heater
11, and temperature sensor opening 13d receives probe 18a (refer to FIG. 15) of heater
temperature sensor 18 that detects, as the heater temperature detecting means, the
temperature of the heating area (described later) that undergoes direct heating by
plane heater 11.
[Keep plate]
[0059] FIGS. 12A to 12C illustrate keep plate 14 that is mounted to upper heating compartment
plate 10 while covering a top of first heat insulator 13. FIG. 12A is a plan view
of keep plate 14. FIG. 12B is an end elevational view of keep plate 14 of FIG. 12A,
taken along line 12B-12B. FIG. 12C is an end elevational view of keep plate 14 of
FIG. 12A, taken along line 12C-12C.
[0060] As shown in FIGS. 12A to 12C, keep plate 14 that is mounted to upper heating compartment
plate 10 is formed with curved-surface area 14a that has curved surfaces similar to
the curved surfaces of heat-generating area 10a of upper heating compartment plate
10. Keep plate 14 functions to press plane heater 11 against heat-generating area
10a of upper heating compartment plate 10 via first heat insulator 13, so that plane
heater 11 is closely fitted to heat-generating area 10a with no clearance throughout
its entire area. Keep plate 14 is formed with pressing parts 14b in positions respectively
facing inner heater 20 and outer heater 21 of plane heater 11. Pressing parts 14b
formed are continuous projections each projecting toward plane heater 11 and press
inner heater 20 and outer heater 21 of plane heater 11 via first heat insulator 13.
Because of being formed with pressing parts 14b as described above, keep plate 14
has increased rigidity. In cases where there is a part where close fitting is poor,
this part can be provided with pressing part 14b for improvement, whereby upper heating
compartment plate 10 can undergo a uniform temperature rise.
[0061] As shown in the end elevational view of FIG. 12B, a longitudinal section (taken
along a left-right line in FIG. 12A) of curved-surface area 14a of keep plate 14 is
substantially defined by a curve.
Similarly, a transverse section (taken along an up-down line in FIG. 12A) of curved-surface
area 14a of keep plate 14 is substantially defined by a curve as shown in the end
elevational view of FIG. 12C. Thus, curved-surface area 14a of keep plate 14 has the
three-dimensional curved surface concavely facing the heating compartment (downward).
In the present exemplary embodiment, a curvature of the longitudinal curve of curved-surface
area 14a differs from a curvature of the transverse curve of curved-surface area 14a.
The longitudinal curvature is smaller than the transverse curvature. Curved-surface
area 14a is not limited to this and may have a longitudinal curvature that is greater
than its transverse curvature. As described above, curved-surface area 14a of keep
plate 14 has the curved surfaces similar to the curved surfaces of heat-generating
area 10a of upper heating compartment plate 10.
[0062] As shown in FIG. 12A, keep plate 14 is formed with, in its center, engagement part
mounting hole 14c for allowing passage of threaded part 19c (refer to FIG. 13) of
locking tool (stepped screw) 19 that is screwed to keep plate engagement part 10c
protrusively provided to upper heating compartment plate 10.
[0063] FIG. 13 is a sectional view describing a method of screwing stepped screw 19, which
is the locking tool, to keep plate engagement part 10c of upper heating compartment
plate 10 so that keep plate 14 is mounted to upper heating compartment plate 10 to
play vertically. In FIG. 13, part (a) illustrates stepped screw 19 that is in the
middle of being screwed to keep plate engagement part 10c, while part (b) illustrates
an assembled condition with stepped screw 19 screwed to keep plate engagement part
10c. As shown in FIG. 13, stepped screw 19 is formed of head 19a, cylinder 19b, and
threaded part 19c with cylinder 19b having a larger diameter than threaded part 19c.
[0064] As shown in part (a) of FIG. 13, head 19a of stepped screw 19 abuts keep plate 14
when stepped screw 19 is in the middle of being screwed to keep plate engagement part
10c. In the structure of the present exemplary embodiment, after head 19a of stepped
screw 19 abuts keep plate 14 as shown in part (a) of FIG. 13, screwing is performed
by a predetermined pitch, whereby cylinder 19b of stepped screw 19 abuts keep plate
engagement part 10c of upper heating compartment plate 10. In this way, the screwing
of stepped screw 19 to keep plate engagement part 10c is completed, and the assembling
is completed.
[0065] FIG. 14 illustrates heat-generating area 10a that has expanded and risen when heat-generating
area 10a of upper heating compartment plate 10 has been heated to a high temperature
by plane heater 11 during use of the thermal cooking device. Even when heat-generating
area 10a rises due to its expansion, cylinder 19b of stepped screw 19 is vertically
slidable in engagement part mounting hole 14c of keep plate 14 as shown in FIG. 14.
For this reason, keep plate 14 does not rise in a manner similar to heat-generating
area 10a that rises due to its expansion, and plane heater 11 is always held pressed
against heat-generating area 10a under a predetermined pressure or more by keep plate
14. Because plane heater 11 is always pressed against heat-generating area 10a by
keep plate 14 as described above, plane heater 11 is held closely fitted to heat-generating
area 10a with no clearance during the cooking operation of the thermal cooking device
according to the present exemplary embodiment.
[0066] As shown in the plan view of keep plate 14 of FIG. 12A, keep plate 14 is provided
with temperature sensor mounting part 14d and terminal mounting part 14e. Temperature
sensor mounting part 14d is a part where heater temperature sensor 18 such as a thermistor
is mounted to detect the temperature of the area that is heated directly by heat from
plane heater 11. Terminal mounting part 14e is where terminal part 24 having the terminals
for inner heater 20 and outer heater 21 of plane heater 11 is mounted. The terminals
of terminal part 24 are connected to a power supply unit that is drivingly controlled
by controller 7 of the thermal cooking device.
[0067] FIG. 15 is an enlarged sectional view illustrating heater temperature sensor (thermistor)
18 mounted in temperature sensor mounting part 14d of keep plate 14. It is to be noted
that an area indicated by reference mark XV in above-mentioned FIG. 4 is shown enlarged
in the sectional view of FIG. 15. As shown in FIG. 15, probe 18a of heater temperature
sensor 18 is disposed in temperature sensor opening 13d formed in first heat insulator
13. Temperature sensor opening 13d defines the heating area (heating space) that undergoes
direct heating by plane heater 11. Accordingly, probe 18a of heater temperature sensor
18 is disposed in this heating area (heating space), which is heated directly by plane
heater 11. In the present exemplary embodiment, the heating area (heating space) is
formed right above inner heater 20 of plane heater 11 to be heated directly by inner
heater 20. With heater temperature sensor 18 detecting the temperature of the heating
area that is heated directly by inner heater 20, based on this heater temperature
information and the internal compartment temperature information from internal compartment
temperature sensor 9 that detects the internal temperature of heating compartment
4, controller 7 drivingly controls the heat source of plane heater 11 and heat sources
of the other various thermal cooking means that are used in the thermal cooking device.
[0068] FIG. 16 is a perspective view of plane heater unit 8 with above-mentioned upper heating
compartment plate 10 being mounted with plane heater 11, first heat insulator 13,
keep plate 14, and others.
As shown in FIG. 16, keep plate 14 of plane heater unit 8 is mounted over heat-generating
area 10a of upper heating compartment plate 10.
[0069] FIGS. 17A to 17C illustrate plane heater unit 8. FIGS. 17A is a plan view of plane
heater unit 8. FIG. 17B is a sectional view of plane heater unit 8 of FIG. 17A, taken
along line 17B-17B. FIG. 17C is a sectional view of plane heater unit 8 of FIG. 17A,
taken along line 17C-17C.
[0070] As shown in FIGS. 17A to 17C, plane heater unit 8 is a substantially integral structure,
forming the ceiling wall of heating compartment 4. As shown in the sectional view
of FIG. 17B, a longitudinal section (taken along a left-right line in FIG. 17A) of
plane heater unit 8 is defined by a curved surface having a substantially uniform
thickness (vertical length). As shown in the sectional view of FIG. 17C, a transverse
section (taken along an up-down line in FIG. 17A) of plane heater unit 8 is similarly
defined by a curved surface having a substantially uniform thickness (vertical length).
Thus, plane heater unit 8 as a whole has the three-dimensional curved surface concavely
facing the heating compartment (downward). It is to be noted that a surrounded area
indicated by reference mark A in the sectional view of FIG. 17B shows where stepped
screw 19, which is the locking tool shown in above-mentioned FIGS. 13 and 14, is screwed.
[Heating control]
[0071] In the thermal cooking device according to the present exemplary embodiment, the
microwave heating unit is provided as the thermal cooking means other than plane heater
unit 8 having the above structure. This microwave heating unit includes a magnetron
that makes microwaves, and radiates the microwaves made by the magnetron from its
antenna via a wave guide. The antenna that radiates the microwaves into heating compartment
4 is disposed below the bottom wall of heating compartment 4 and radiates the microwaves
in the form of, for example, circularly polarized waves from below heating compartment
4 into heating compartment 4. The antenna is capable of radiating microwaves having
directivity and enables uniform heating of the interior of heating compartment 4 by
being rotated.
[0072] The other thermal cooking means of the thermal cooking device according to the present
exemplary embodiment include the steam heating unit that intensively ejects water
vapor into the heating compartment for thermal cooking and the hot-air circulation
unit that heats or cooks food by circulating hot air in heating compartment 4. The
steam heating unit has the water tank inside main body 1 and intensively ejects into
heating compartment 4 water vapor that is generated by heating water to a high temperature
by means of the steam heaters of the boiler. The hot-air circulation unit sucks air
from heating compartment 4, heats the air by means of a rear heater provided behind
heating compartment 4, and supplies the heated air to the interior of heating compartment
4.
[0073] As described above, plane heater unit 8, the microwave heating unit, the steam heating
unit, and the hot-air circulation unit are provided as the thermal cooking means in
the thermal cooking device of the present exemplary embodiment. According to the cooking
content, the thermal cooking means is selected. Depending on cases, the thermal cooking
means are drivingly controlled simultaneously or in combination. It is to be noted
that heating control using plane heater unit 8 is mainly described in the present
exemplary embodiment.
[0074] As shown in above-mentioned FIG. 15, probe 18a of heater temperature sensor 18 is
received by temperature sensor opening 13d formed in first heat insulator 13 and thus
is disposed in the heating area (heating space) that undergoes direct heating by inner
heater 20 of plane heater 11. Heater temperature sensor 18 detects the temperature
of the space heated directly by inner heater 20 and transmits the detected temperature
as the heater temperature information to controller 7 (refer to FIG. 18). Based on
the heater temperature information as well as the internal compartment temperature
information from internal compartment temperature sensor 9 that detects the internal
temperature of heating compartment 4, controller 7 controls, for example, the heat
source and a driving source in the thermal cooking operation according to, for example,
the cooking content set by the user.
[0075] In the present exemplary embodiment, heater temperature sensor 18 detects the temperature
of the heating area (heating space) that undergoes direct heating by inner heater
20, so that in the thermal cooking operation using inner heater 20, controller 7 can
perform temperature control based on the highly accurate heater temperature information
from heater temperature sensor 18. As described later, a rapid heating operation is
carried out using inner heater 20 with a greater heater output in the present exemplary
embodiment to cause a rapid temperature rise in heating compartment 4, so that the
heater temperature information is effective in this rapid heating operation.
[0076] In a conventional thermal cooking device, as described in [SUMMARY OF THE INVENTION],
on and off control of a plane heater based on a detected internal compartment temperature
is performed such that an interior of a heating compartment reaches a preset temperature.
As such, the plane heater is once turned off far ahead of a time when the internal
compartment temperature reaches the preset temperature in the conventional thermal
cooking device, and an on and off operation of the plane heater is repeated thereafter
to gradually bring the internal compartment temperature closer to the preset temperature.
It is thus difficult for the internal compartment temperature to reach the preset
temperature with high accuracy through the use of the plane heater, and a length of
time is required until the preset temperature is reached.
[0077] In the thermal cooking device according to the present exemplary embodiment, controller
7 performs the temperature control in the thermal cooking operation based on the heater
temperature information from heater temperature sensor 18 and the internal compartment
temperature information. Particularly in the rapid heating operation where a rapid
temperature rise is caused in heating compartment 4 so that a preset temperature is
reached within a short period of time, a control operation is carried out based on
the heater temperature information indicative of the temperature of the heating area
heated by inner heater 20. Accordingly, controller 7 can cause the heating area to
be heated rapidly to the preset temperature by means of inner heater 20 and thus can
cause the internal temperature of heating compartment 4 to rise rapidly. As described
later, current that is input to inner heater 20 can be controlled to a desired value
in the present exemplary embodiment, so that the heater output of inner heater 20
can be set at a desired value. As such, controller 7 can maintain the internal compartment
temperature at the preset temperature with high accuracy by controlling the current
that is input to inner heater 20 based on the internal compartment temperature information
and the heater temperature information after the internal compartment temperature
has reached the preset temperature. Consequently, the thermal cooking device according
to the present exemplary embodiment can significantly shorten a length of time until
the internal compartment temperature reaches the preset temperature and can maintain,
with high accuracy, the internal compartment temperature at the preset temperature
for a predetermined period of time.
[Thermal cooking operations]
[0078] FIG. 18 shows a part of a circuit diagram for control of the thermal cooking means
in the thermal cooking device according to the present exemplary embodiment. The heat
sources of the thermal cooking means in the thermal cooking device of the present
exemplary embodiment include inner heater 20 and outer heater 21 of plane heater unit
8, steam heaters 26 of the steam heating unit, rear heater 27 of the hot-air circulation
unit, and magnetron 28 of the microwave heating unit (refer to FIG. 18). The hot-air
circulation unit uses circulation fan motor 29.
[0079] As shown in the circuit diagram of FIG. 18, inner heater 20, outer heater 21, steam
heaters 26, rear heater 27, and circulation fan motor 29 are respectively connected
to corresponding switching elements to each undergo on and off control. Magnetron
28 is a microwave generating means of the microwave heating unit and is connected
to an inverter circuit that serves as the driving power source. In the present exemplary
embodiment, triode for alternating current (TRIAC) 30 is used as the switching element
in driving control of inner heater 20, so that the current that is input to inner
heater 20 can be controlled to a desired value. For outer heater 21, relay 31 is used
as the switching element to simply switch on and off outer heater 21. While the present
exemplary embodiment is described with relay 31 being used as the switching element
that simply switches on and off outer heater 21, a TRIAC may be used as the switching
element for outer heater 21 as in the case of inner heater 20 so that input power
can be controlled variably in a stepless manner.
[0080] Rated power is predetermined for the thermal cooking device, so that power greater
than the rated power cannot be consumed. The thermal cooking device according to the
present exemplary embodiment is structurally capable of thermal cooking using the
plurality of thermal cooking means, and the power that is consumed by the heat sources
to be activated is always controlled to not more than the rated power by controller
7. The control of plane heater unit 8 in particular is characteristic in the thermal
cooking device of the present exemplary embodiment.
[0081] Heater 25 of plane heater unit 8 is the one heat source formed of inner heater 20
and outer heater 21 with respective maximum heater outputs of inner heater 20 and
outer heater 21 being, for example, 900 W and 700 W, in the present exemplary embodiment.
As such, a total of the respective maximum heater outputs of inner heater 20 and outer
heater 21 exceeds general-home rated power (1500 W = 15 A (rated current) × 100 V).
As shown in FIG. 18, inner heater 20 is drivingly controlled by means of TRIAC 30
that serves as the switching element in the thermal cooking device according to the
present exemplary embodiment. Accordingly, inner heater 20 can be driven by a control
signal that is input to TRIAC 30 such that its heater output can be varied in the
stepless manner in the range of from 300 W to 900 W.
[0082] Specific examples are hereinafter used to describe the thermal cooking operations
using the thermal cooking means of the thermal cooking device according to the present
exemplary embodiment.
[0083] In cases where thermal cooking is carried out using only plane heater unit 8 with
the substantially entire area of the ceiling wall of heating compartment 4 being the
heat generator, for example, inner heater 20 of plane heater 11 is drivingly controlled
such that its heater output is 700 W, while outer heater 21 is in an on position with
its heater output being 700 W. In this way, heating compartment 4 can be heated by
plane heater 11 having a total heater output of 1400 W.
[0084] In cases where thermal cooking is carried out in heating compartment 4 by use of
the ceiling wall surface of plane heater unit 8 and microwaves of the microwave heating
unit from below the bottom wall, for example, inner heater 20 of plane heater 11 is
set to the maximum heater output of 900 W while outer heater 21 is in an off condition
(0 W). Heating compartment 4 is thus heated from above by plane heater 11 having a
total heater output of 900 W. Meanwhile, the microwave heating unit used as the other
thermal cooking means can thermally cook food placed on heat-generating pan 6 by heating
heat-generating pan 6, which is accommodated by heating compartment 4, with those
that include magnetron 28 consuming, for example, 450 W of power.
[0085] In the other example, food placed on heat-generating pan 6 can be thermally cooked
with outer heater 21 being in the off condition (0 W), with the heater output of inner
heater 20 being 430 W, and with those that include magnetron 28 in the microwave heating
unit consuming 550 W of power. As described above, even when plane heater unit 8 and
the microwave heating unit are used for thermal cooking, a desired cooking operation
can be carried out with consumption of power that is not more than the general-home
rated power (1500 W = 15 A (rated current) × 100 V).
[0086] The use of plane heater unit 8 and the microwave heating unit in the thermal cooking
device of the present exemplary embodiment enables intensive heating of a central
portion of heating compartment 4. With the heater output of 900 W in plane heater
11 as opposed to 650 W in the conventional cases, the heater output per unit area
is 1.6 times greater. Inner heater 20 in particular has the higher heater output than
outer heater 21. As such, in the structure of the present exemplary embodiment, a
central portion of the ceiling wall surface of heating compartment 4 can be heated
rapidly by inner heater 20 having the higher heater output and thus becomes a heat
generator. This heat generator can radiate heat intensively toward the central portion
of heating compartment 4. Moreover, because the heater wire is densely wound during
the formation, upper heating compartment plate 10 can undergo a more uniform temperature
rise.
[0087] Meanwhile, the antenna of the microwave heating unit can radiate microwaves (circularly
polarized waves) intensively toward the central portion of heating compartment 4 from
below heating compartment 4 in the structure of the present exemplary embodiment.
Heating compartment 4 accommodates heat-generating pan 6 on which food to be cooked
is placed. The heat generator that absorbs the microwaves to generate heat is embedded
at mounting surface 33 of heat-generating pan 6. Consequently, the food on the mounting
surface of heat-generating pan 6 undergoes heating that is effected from below by
the microwave heating unit via heat-generating pan 6 heated by the heat generator
while being heated intensively by receiving the upper heat that is radiated by the
ceiling wall's central portion heated by plane heater unit 8. This means that the
thermal cooking device according to the present exemplary embodiment is structurally
capable of rapidly heating the food on heat-generating pan 6, which is accommodated
by heating compartment 4, to a high temperature from above and below the food.
[0088] FIG. 19 is a perspective view of heat-generating pan 6 that is used in the thermal
cooking device according to the present exemplary embodiment. FIG. 20 is a plan view
of heat-generating pan 6 shown in FIG. 19. As shown in FIGS. 19 and 20, when viewed
in a plane, heat-generating pan 6 is rectangular with its outer border 34 having the
shape of an outwardly spreading flange. A central portion surrounded by outer border
34 is recessed with its bottom being mounting surface 33. Mounting surface 33 is shaped
to have irregularities. The irregularities of mounting surface 33 are such that valleys
and ridges are alternately formed, running obliquely to a left-right line of mounting
surface 33 (to a left-right line of the thermal cooking device). In the present exemplary
embodiment, the obliquely running valleys and ridges each extend at an angle of about
45 degrees from the left-right line.
[0089] A central portion of mounting surface 33 of heat-generating pan 6 is provided with
area boundary marks 32 to have its rectangular shape defined. Rapid heating area B
is located internal to area boundary marks 32 and designates an area where rapid thermal
cooking of a cooking object is intensively carried out using inner heater 20 of above-mentioned
plane heater unit 8 and microwave heating that is effected by the microwave heating
unit. As such, rapid thermal cooking can be carried out when the user places food
to be cooked in rapid heating area B located internal to area boundary marks 32 of
heat-generating pan 6. It is to be noted that area boundary marks 32 may each, for
example, have the shape of a projection or a recess or be printed to be identifiable
visually and tactually with ease.
[0090] As described above, the thermal cooking device according to the present exemplary
embodiment is structurally capable of rapidly raising the internal compartment temperature
and maintaining the internal compartment temperature (the temperature of the upper
heating compartment plate) at a constant temperature when performing thermal cooking
using at least the plane heater as the thermal cooking means.
[0091] The thermal cooking device according to the present exemplary embodiment enables
the internal compartment temperature (the temperature of the upper heating compartment
plate) to reach a preset temperature with high accuracy and can shorten a length of
time until the internal compartment temperature reaches the preset temperature, thus
being structurally capable of shortening a length of cooking time.
[0092] Although the rated power is specified for the thermal cooking device of the present
exemplary embodiment, particularly the thermal cooking device intended for general
home use, the plurality of power units that consume the total amount of power exceeding
the rated power can be used to rapidly start up the interior of the heating compartment
with desired high heating power for rapid thermal cooking.
INDUSTRIAL APPLICABILITY
[0093] A thermal cooking device of the present disclosure is structurally capable of rapidly
raising an internal compartment temperature to a desired temperature to achieve a
shortened length of cooking time and thus is a cooking device having a high market
value.
REFERENCE MARKS IN THE DRAWINGS
[0094]
- 1
- main body
- 2
- door
- 3
- handle
- 4
- heating compartment
- 5
- setting part
- 6
- heat-generating pan
- 7
- controller
- 8
- plane heater unit
- 9
- internal compartment temperature sensor
- 10
- upper heating compartment plate (ceiling wall)
- 10a
- heat-generating area
- 10b
- honeycomb area
- 10c
- keep plate engagement part
- 10d
- fastener
- 11
- plane heater
- 12
- pressing tool
- 13
- first heat insulator
- 14
- keep plate
- 15
- insulating sheet
- 16
- heat shield plate
- 17
- second heat insulator
- 18
- heater temperature sensor (thermistor)
- 18a
- probe
- 19
- locking tool (stepped screw)
- 20
- inner heater
- 21
- outer heater
- 22
- upper insulator
- 23
- lower insulator
- 24
- terminal part
- 25
- heater
- 26
- steam heater
- 27
- rear heater
- 28
- magnetron
- 29
- circulation fan motor
- 30
- TRIAC
- 31
- relay
- 32
- area boundary mark
- 33
- mounting surface
- 34
- outer border
1. Wärmekochvorrichtung, die Folgendes umfasst:
eine Heizkammer (4), in der ein Kochobjekt erhitzt wird;
ein flaches Heizelement (11), das über einer Deckenwand (10) der Heizkammer (4) vorgesehen
ist, wobei das flache Heizelement (11) eine Wärmequelle ist, die aus einem inneren
Heizelement (20), das direkt über einem zentralen Abschnitt der Deckenwand (10) angeordnet
ist, und einem äußeren Heizelement (21), das das innere Heizelement (20) umgibt, gebildet
ist; und
eine Steuerung (7), die das innere Heizelement (20) und das äußere Heizelement (21)
des flachen Heizelements (11) steuert,
wobei die Deckenwand (10) der Heizkammer (4) eine dreidimensional gebogene Oberfläche
aufweist, die konkav zu der Heizkammer (4) zeigt,
wobei das flache Heizelement (11) so fixiert ist, dass es über eine gesamte Fläche
des flachen Heizelements (11) engen Kontakt mit der Deckenwand (10) hat,
wobei die Deckenwand (10) eine wärmeerzeugende Fläche (10a) aufweist, an der das flache
Heizelement (11) direkt montiert ist, dadurch gekennzeichnet, dass:
die wärmeerzeugende Fläche (10a) mit mehreren Flächen (10b) ausgebildet ist, die durch
Rillen voneinander getrennt sind.
2. Wärmekochvorrichtung nach Anspruch 1, wobei die dreidimensional gebogene Oberfläche
einer Deckenwandfläche der Heizkammer (4) in einer Draufsicht rechteckig ist und eine
Längskrümmung und eine Querkrümmung aufweist, die sich voneinander unterscheiden.
3. Wärmekochvorrichtung nach Anspruch 1, wobei jede der mehreren Flächen (10b) eine Deformationskraft
absorbiert, die aus einer Expansion oder Kontraktion folgt, die durch Wärme des flachen
Heizelements verursacht wird, und wobei die mehreren Flächen (10b) eine identische
Form aufweisen.
4. Wärmekochvorrichtung nach Anspruch 1, wobei jede der mehreren Flächen (10b) eine Polygonform
aufweist und eine Deformationskraft absorbiert, die aus einer Expansion oder Kontraktion
folgt, die durch Wärme des flachen Heizelements verursacht wird.
5. Wärmekochvorrichtung nach Anspruch 1, wobei jede der mehreren Flächen (10b) eine Wabenform
aufweist und eine Deformationskraft absorbiert, die aus einer Expansion oder Kontraktion
folgt, die durch Wärme des flachen Heizelements verursacht wird.
6. Wärmekochvorrichtung nach Anspruch 1, wobei das flache Heizelement (11) über einen
Wärmeisolator (13) durch eine Halteplatte (14), die an der Deckenwand (10) montiert
ist, so gehalten wird, dass es Bewegungsfreiheit hat und eine dreidimensional gebogene
Oberfläche aufweist.
7. Wärmekochvorrichtung nach Anspruch 6, wobei
die Halteplatte (14) in Bereichen, die jeweils zu dem inneren Heizelement (20) und
dem äußeren Heizelement (21) zeigen, mit Presselementen (14b) ausgebildet ist, die
in Richtung des inneren Heizelements (20) und des äußeren Heizelements (21) vorstehen,
und
die Presselemente (14b) das innere Heizelement (20) und das äußere Heizelement (21)
über den Wärmeisolator (13) pressen.
8. Wärmekochvorrichtung nach Anspruch 1, wobei
eine Summe der jeweiligen maximalen Heizelement-Ausgangsleistung des inneren Heizelements
(20) und des äußeren Heizelements (21) eine Nennleistung der Wärmekochvorrichtung
überschreitet, und
die Steuerung (7) Leistung steuert, die dem inneren Heizelement (20) zugeführt wird,
um zu verhindern, dass eine Summe der jeweiligen Heizelement-Ausgangsleistung des
inneren Heizelements (20) und des äußeren Heizelements (21) die Nennleistung der Wärmekochvorrichtung
überschreitet.
9. Wärmekochvorrichtung nach Anspruch 1, die ferner einen Heizelement-Temperatursensor
(18) umfasst, der eine Temperatur einer Fläche detektiert, die durch das innere Heizelement
(20) direkt geheizt wird,
wobei die Steuerung (7) auf der Basis der Heizelement-Temperaturinformationen, die
durch den Heizelement-Temperatursensor (18) detektiert werden, eine Steuerung durchführt,
die das innere Heizelement (20) startet, um zu bewirken, dass das innere Heizelement
(20) eine Temperatur erreicht, die zuvor für die Heizkammer (4) eingestellt wurde.
10. Wärmekochvorrichtung nach Anspruch 1, wobei wenigstens eine Stirnfläche des flachen
Heizelements der Deckenwand (10) der Heizkammer (4) eine Schicht aus schwarzem Silizium
aufweist.
11. Wärmekochvorrichtung nach Anspruch 1, wobei wenigstens die Deckenwand (10) der Heizkammer
(4) eine Selbstreinigungsschicht bei einer Heizkammer-Stirnfläche der Deckenwand (10)
aufweist.