JPH0577930B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a cooking device, such as an electric oven or a microwave oven with a heater, that heats an object to be heated stored in a heating chamber using the heat of a heater.

Conventional technology Microwave ovens equipped with a heater generally use a heating method using a heater, and a top-bottom heater type that uses sheathed heaters on the top and bottom of the heating chamber, which mainly uses heat radiation and natural convection, and a top-bottom heater type that uses a heater outside the heating chamber. It can be roughly divided into hot air type, which heats the food by forcing the heat generated by the heat to circulate into the heating chamber using a circulation fan. The former has good performance as an electric oven, has a simple configuration, and can be made at low cost, so it is the mainstream.

FIG. 6 is a sectional view showing a conventional heating cooker with upper and lower heaters.

In FIG. 6, the heating chamber 1 is provided with an upper heater 2 at the upper part and a heater 3 at the lower part, and the food 5 placed on the saucer 4 is heated by the heater and cooked.
Furthermore, a magnetron 6 is provided and radio waves are irradiated into the heating chamber 1 through a waveguide 7 to heat the food 5 by radio waves. This is a so-called microwave oven with multiple heating of a heater and radio waves.

FIG. 7 is a perspective view of a heater used in a conventional heating cooker.

Problems to be Solved by the Invention However, in such a conventional heating cooker, the upper heater 2 and the lower heater 3 are exposed in the heating chamber 1, so the effectiveness of the heating chamber is reduced by this amount. In order to be able to store even large foods due to the narrow volume, it was necessary to make the heating chamber larger by the size occupied by the heater. As a result, the external size is large and a large installation space is required, making the cooking device difficult to use.

In addition, if the heater is exposed in the heating chamber, even if dirt from food oil or broth is scattered on the heating chamber wall, the heater will get in the way and be difficult to clean, making it easier to use. was wrong.

Furthermore, since the heaters 1 and 2 are exposed in the heating chamber, the food 5 directly receives the radiant heat from the upper heater 1, causing problems such as local heating unevenness along the shape of the heater 1. .

In order to solve these problems, there is a configuration plan in which the heater is placed outside the heating chamber and installed in a planar configuration, but due to thermal deformation of the heating chamber wall surface, undulations occur and there is a problem with the planar heater. Contact tends to be localized. This local contact causes uneven heating of the object to be heated, and also leads to problems such as wire breakage and insulation deterioration due to local heating of the sheet heater itself.

The present invention solves these conventional problems, and provides excellent thermal efficiency, easy to use by clearing the heating chamber, and highly reliable cooking with good heating performance and no failures. It provides equipment.

Means for Solving the Problems In the heating cooker of the present invention, the heater is formed into a planar shape and is arranged so as to cover almost the entire area outside the ceiling surface of the heating chamber. It is constructed of a metal plate with a low coefficient of expansion, and is placed outside the heating chamber, i.e.
A bulge is formed on the side of the sheet heater to ensure uniform and reliable surface contact between the sheet heater and the ceiling of the heating chamber.

Effect According to the present invention, the planar heater is provided outside the ceiling surface of the heating chamber, and since the ceiling surface of the heating chamber has a bulge in advance on the side of the planar heater, as heating progresses, the heat on the ceiling surface increases. Due to the expansion, the heating chamber ceiling surface further curves into an arch toward the planar heater side. At this time, if the heating chamber ceiling surface is just a flat metal plate with a high coefficient of thermal expansion, it will not be able to absorb the thermal expansion and will deform into a wave shape during curving and locally buckle. It will not be possible to make it stick to the ceiling surface. However, if the ceiling surface of the heating chamber is made of a metal plate with a low coefficient of thermal expansion as in the present invention, the amount of deformation will be minimal, there will be no wavy deformation, and the entire surface will be uniformly curved.

Due to these effects, it is possible to effectively heat the food even if the heating element is provided outside the heating chamber, and of course, the heat distribution is made uniform, so that even baking can be achieved. Further, since there is no need for an exposed heater inside the heating chamber, the effective volume within the heating chamber is increased, and the usability can be improved such as easy cleaning.

Embodiment A heating cooker according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a front sectional view showing the structure of a cooking device according to the present invention. In FIG. 1, a planar heater 8 is provided in close contact with the outer surface of the ceiling surface 1a or the bottom surface of the heating chamber 1. The planar heater 8 is fixed by a metal plate 9 for attaching the heater. 10 is a heat insulating material for preventing heat from escaping to the outside. Furthermore, the magnetron 6 is a waveguide 7
The device is installed to heat the object to be heated 5 placed on the object to be heated plate 4 by high frequency. With the above configuration, the object to be heated 5 can be heated by both heater heating and high frequency heating.

FIG. 2 is a perspective view showing the structure of each component of the upper planar heater section, and FIG. 3 is a partial sectional view showing the structure of the planar heater 8 in detail. In FIGS. 2 and 3, the planar heater 8 has a structure in which a heating element 8a is wound around a winding frame 8b made of a heat-resistant insulator such as mica, and the top and bottom of the frame 8b are sandwiched between insulating plates 8c also made of mica or the like. It is. Heater mounting plate 9
has several elongated holes radiating from the center, and the stepped screws 11 are pushed into the elongated holes to complete the heating chamber 1.
A sheet heater 8 is fastened to the ceiling surface 1a of the roof 1a in a sandwiched manner. A locking metal fitting 12 fixed to the ceiling surface of the heating chamber 1 by welding or the like is provided in the central part, and after inserting the planar heater 8, the locking metal fitting 12 is bent in a twisting manner and brought into close contact with the ceiling surface 1a. ing. Here, the ceiling surface 1a of this heating chamber 1 has a gentle bulge on the side of the sheet heater.

With the above configuration, heating progresses and the sheet heater 8
Even if the mounting plate 9 undergoes thermal expansion, the state of close contact between the planar heater 8 and the ceiling surface of the heating chamber 1 will not change at all times because the central portion is fixed by pressure with the locking fitting 12. Moreover, the pressure in the vertical direction of the stepped screw 11 is
Since it is not very strong and is tightened in the elongated hole, the mounting plate 9 expands in the plane direction. However, since the ceiling surface 1a of the heating chamber 1 is welded around it and is formed into a box shape, the force of thermal expansion is
It works vertically and tries to curve upwards. At this time, if the ceiling surface is just a flat plate, it may curve in either the up or down direction, deform into waves in areas other than the periphery, and cause local buckling as thermal expansion progresses. However, as shown in the figure,
If the ceiling surface 1a of the heating chamber 1 is made of a metal plate with a small coefficient of thermal expansion (for example, SUS430, etc.) and a bulge is formed on the side of the sheet heater, the amount of deformation can be kept small and the bulge direction can be stably maintained. It will be curved to. That is, the planar heater 8 and the heating chamber 1
The adhesion of the ceiling surface 1a is strengthened, and stable heat distribution with good thermal efficiency can be obtained.

4 and 5 are partial cross-sectional views showing other embodiments of a method of fixing the peripheral edge of the sheet heater 8. FIG. The configuration in which the planar heater 8 is held down by the heater mounting plate 9 is the same. In FIG. 4, a hole is provided in a single surface of the ceiling surface 1a of the heating chamber 1, and a stepped screw 11 is pushed into the hole and fastened to the heater mounting plate 9. In other words, the stepped portion of the stepped screw 11 allows movement in the plane direction. In Fig. 5, heating chamber 1
In this method, a substantially Z-shaped metal fitting 13 is provided on the ceiling surface 1a, and the heater mounting plate 9 is inserted between the metal fitting 13 and the ceiling surface 1a, and fixed with a slight gap.
Even with the fixing method shown in FIGS. 4 and 5, the effect remains the same.

Effects of the Invention As described above, according to the cooking device of the present invention, the following effects can be obtained.

(1) In order to obtain good heat distribution, which is a feature of the sheet heater, the most important condition is that the sheet heater has good adhesion to the heating chamber ceiling surface both in cold and hot conditions. By making the heating chamber ceiling protrude toward the planar heater side and constructing it with a metal plate with a low coefficient of thermal expansion, stable adhesion can be achieved, resulting in efficient heat conduction and shortening cooking time. This makes it possible to achieve heating cooking with excellent thermal efficiency.

(2) Stable adhesion eliminates local heating by the heater, provides uniform heat distribution without uneven heating, and improves cooking performance.

(3) The same stable adhesion eliminates local heating of the heater, creating a highly safe heating cooker that is free from failures due to disconnection of the heating element, insulation deterioration, etc., as well as dangers such as electric shock and fire. can.

(4) A highly efficient heating chamber can be achieved even when the heater is placed outside the heating chamber, so compared to the conventional configuration in which the heater is placed inside the heating chamber, the heating chamber has no unnecessary protrusions and has a more streamlined shape. To provide an easy-to-use heating cooking device that is easy to clean and can be easily wiped off even if food is scattered on the wall of a heating chamber and becomes dirty.

(5) Since the heater does not extend into the heating chamber, the effective volume within the heating chamber increases, allowing even large foods to be cooked. Furthermore, if the heating volume is the same, the external size can be made smaller by that amount, making it possible to realize a compact and easy-to-use heating cooker.

(6) The heating chamber wall surface always deforms in a fixed direction during heating, and only slight deformation is required, so it is possible to design a heating chamber that provides stable heating distribution performance even during high frequency heating. Heating unevenness can also be reduced.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a heating cooker according to an embodiment of the present invention, FIG. 2 is an exploded perspective view showing the configuration of the heater mounting part and heater of the same heating cooker, and FIG. 3 is a heater of the same heating cooker. 4 and 5 are enlarged sectional views of the heater mounting portion showing other embodiments of the heating cooker, FIG. 6 is a sectional view of the conventional heating cooker, and FIG. 7 is an enlarged sectional view of the mounting portion. is a perspective view of a heater of the heating cooker. 1... Heating chamber, 1a... Ceiling surface, 2... Upper heater, 3... Lower heater, 8... Planar heater.

Claims (1)

[Claims] 1. A heating chamber for storing an object to be heated, and a planar heating element for heating the object to be heated, and the planar heating element is closely attached to the outer surface of a heating chamber wall constituting the heating chamber via a heat-resistant insulator. The heating chamber wall surface in which the planar heating element is disposed is made of a metal plate having a coefficient of thermal expansion smaller than that of the other heating chamber wall surfaces, and is formed in a shape that bulges toward the planar heating element side. vessel.