JPH04281117A - Electronic oven - Google Patents

Abstract

PURPOSE:To improve the efficiency of oven grill heating and, at the same time, reduce the unevenness in heating in an electronic oven by setting at a specified value the frequency of the high frequency for dielectric heating that is generated by a high frequency generating means. CONSTITUTION:An electronic oven is provided with an oven cooking heater 6 on the ceiling plate and on the floor plate of the heating chamber 5 respectively, and in the machine chamber a magnetron 7 is installed as means of generating high frequency. In this case the frequency of the high frequency generated from the magnetron 7 is set at 5.8GHHz. With this arrangement the minimum dimension H of the heating chamber is made shaft and the efficiency of the oven grill heating is raised. And, by using the frequency of 5.8GHHz that is a short wavelength the unevenness of heating in the heating chamber 5 is reduced.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave oven having an oven function.

0003

[Prior Art] Currently, general household microwave ovens use high frequency (
2.45 GHz is used for heating using microwaves. Furthermore, microwave ovens that have a heater installed in the heating chamber and have an oven/grill function are also becoming common. In the case of high frequency heating, the size of the heating chamber is determined as follows. The heating chamber is considered to be a hexagonal-to-cavity resonator, and the resonant wavelength λr of the hexagonal-to-cavity resonator is:
It is expressed by the following formula, where m, n, and p are integers.

λr=2/[(m/a)2 +(n/b)2
+(p/c)2]1/2...(1) a, b, c are the dimensions of each side of the rectangular hexagonal cavity resonator, as shown in Figure 8, and m, n, p are It represents the number of peaks of standing waves in the heating chamber. The simplest resonance is one in which one of m, n, and p is zero and the other one, and in this case, the minimum dimensions of a rectangular hexagonal cavity resonator are obtained. From the above formula, (1/a2)+(1/b2)=4/λr2
…(
2) From this, if a=b, a=b=λr/21/2

...(3). Here c is an arbitrary dimension.

[0005] In reality, this dimension causes significant heating unevenness in the heating chamber and is not practical, so m, n, and p are required to be 3 or more, but since the heating chamber becomes too large, products with 2 or more are required. seems to have been adopted. The current microwave oven using a high frequency of 2.45 GHz is λ
When r is 122 mm, the aforementioned minimum dimension is 86.5 mm, but the minimum dimension of the heating chamber of the product is approximately 173 mm.

In the case of high-frequency heating, the place to store the heated object in the heating chamber is at the bottom of the heating chamber because it has the best impedance matching for heated objects of various shapes and materials and allows for uniform heating. . On the other hand, in terms of oven/grill function, the shorter the distance between the heated object and the heater, the higher the heating efficiency, so the instructions are to store the heated object near the top heater. Furthermore, heat from a heater installed at the back of the heating chamber is heated by blowing air through a fan to cause convection inside the heating chamber, thereby heating the object to be heated.

[0007]

[Problems to be solved by the invention] Conventional microwave ovens have
Since the frequency of the high frequency for dielectric heating is 2.45 GHz, the minimum dimension of the heating chamber is approximately 173 mm, and in the case of oven/grill heating, in order to heat both sides, the object to be heated must be separated from the top and bottom heaters. The distance to the vehicle becomes longer, making it impossible to drive efficiently. Moreover, in the case of convection heating, efficiency is low. On the other hand, when performing heating using a combination of high-frequency heating and oven/grill heating, the position of the object to be heated within the heating chamber may have to be changed depending on the heating method, which poses a problem that requires time and effort on the part of the user. Ta.

[0008] Therefore, the present invention provides a microwave oven that has high oven/grill heating efficiency and can appropriately perform heating by combining high frequency heating and oven/grill heating without changing the position of the heated object. The purpose is to

[Configuration of the invention]

0010

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a microwave oven having an oven function, in which the frequency of the high frequency wave for dielectric heating generated from the high frequency generating means is set to 5.8 GHz. The gist is that.

[0011]

[Function] By setting the frequency of the high frequency for dielectric heating to 5.8 GHz, the minimum dimension of the heating chamber becomes approximately 1/2.4 of that when a frequency of 2.45 GHz is used, and the distance between the heater and the object to be heated is reduced. Shorter distance improves oven/grill heating efficiency. By using a frequency of 5.8 GHz, which has a short wavelength, uneven heating within the heating chamber is reduced, and the combination of high-frequency heating and oven/grill heating can be appropriately performed without changing the position of the object to be heated.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are diagrams showing a first embodiment of the present invention.

In FIG. 1, 1 is a microwave oven cabinet, 2 is a door with a radio wave shielding mechanism, 3 is a machine room, 4 is an operation panel, 5 is a heating chamber, and 6 is an oven cooking heater. It is installed on the board side. Although not shown in FIG. 1, a similar heater is also installed on the bottom plate side of the heating chamber 5. The heating chamber 5 receives 5.8 GH from a magnetron as a high frequency generation means installed in the machine room 3.
A high frequency wave (wavelength: 52 mm) of z is supplied via a waveguide, and the object to be heated in the heating chamber 5 is dielectrically heated.

As described above, in this embodiment, by setting the frequency of the high frequency generated from the magnetron to 5.8 GHz, λr in the above equation (3) becomes 2.45.
The minimum dimension of the heating chamber is about 1/2.4 of that when a GHz frequency is used, and the height H of the heating chamber 5 in FIG. 1 is 80 mm.

FIG. 2 shows an example in which a frozen pizza 10 is used as the object to be heated. The high frequency waves emitted from the 5.8 GHz magnetron 7 are guided to the heating chamber 5 through the waveguide 8, and dielectrically heats the frozen pizza 10 placed on the net 9 for fixing the object to be heated to defrost it. After thawing, the food is heated by a heater 6 attached to the top plate and bottom plate of the heating chamber 5. At that time, the distance between the pizza 10 and the heater 6 is close to 40 mm or less, and compared to the case of 2.45 GHz, the heating efficiency is significantly increased, making it possible to save energy and time.

Next, a case where fish is used as the object to be heated will be described. In general, fish is said to be delicious when cooked over high heat to brown the surface and prevent excess moisture from evaporating. The high frequency of 5.8 GHz has a short wavelength of 52 mm and has the characteristic of easily warming the surface of the object to be heated. Therefore, when grilling fish, first heat the surface with the high frequency and then heat it with the heater 6 to ensure that it is evenly delicious. You can get a good baked result. This method is effective for cooking that requires browning.

In the above example, the items to be heated are frozen pizza and fish, but it is also possible to cook toast, gratin, hamburger steak, steak, pancakes, etc. by combining high-frequency heating and heater heating, or by heating only by heater. However, heating efficiency is greatly improved and cooking can be completed in a short time.

FIGS. 3 to 5 show a second embodiment of the invention.

[0020] In this embodiment, the entire microwave oven including the machine room 3 and the cabinet 1 has a structure that can be replaced with a vertical type or a horizontal type. In other words, there is a fixed stand 1 under the microwave oven.
1 is provided, and one end side of the bottom of the microwave oven is a fixed base 11.
are connected to each other by a hinge 12.

When heating a vertically long object to be heated, the microwave oven is placed vertically as shown in FIG. The user can place the microwave oven vertically as follows. Hold the handle 14 and pull it up. At this time, the fixed base 11 does not move, and the microwave oven rotates around the hinge 12. When the microwave oven is rotated 90 degrees, the stopper 13 is pulled out to fix the microwave oven.

FIG. 5 corresponds to the cross-sectional view of FIG. 4, and shows cooking when fish is taken as an example of the object to be heated. The fish 10 suspended from a hanging rod 15 provided in the heating chamber 5 via a hook 16 is heated from both sides at a short distance by heaters 6 installed on the left and right walls. Multiple fish can be stored in the depth direction. The oil 17 that comes out of the fish 10 during heating falls downward, but since the heater 6 is on the side, the oil 17 does not reach the heater 6.
never come into contact. Therefore, it is possible to reduce the smell and smoke peculiar to fish cooking, and the user's effort to clean the inside of the heating chamber 5 can be reduced. The cooking process when placed vertically has been explained using fish as an example, but by placing it vertically, it becomes possible to cook sake, warm milk, etc.

FIGS. 6 and 7 show a third embodiment of the present invention.

[0024] In this embodiment, only the heating chamber, that is, the cabinet part, has a structure that can be replaced with a vertical type or a horizontal type. A guide 18 for attaching the heating chamber is provided on the side surface of the machine room 3 on the cabinet side. FIG. 6 shows a state in which a heating chamber 5a for horizontal cooking is installed, and FIG. 7 shows a state in which a heating chamber 5b for vertical cooking is installed using the same machine room 3. When the heating chamber is made vertical, the same actions and effects as in the second embodiment can be obtained for the object to be heated, such as fish.

[0025]

[Effects of the Invention] As explained above, according to the present invention, since the frequency of the high frequency wave for dielectric heating generated from the high frequency generating means is set to 5.8 GHz, the minimum dimension of the heating chamber can be reduced. The distance between the heater and the object to be heated is shortened, and the efficiency of oven/grill heating can be increased. Moreover, heating unevenness in the heating chamber during dielectric heating is reduced, and a combination of high frequency heating and oven/grill heating can be appropriately performed without changing the position of the object to be heated.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a first embodiment of a microwave oven according to the present invention.

FIG. 2 is a longitudinal sectional view showing the internal configuration of FIG. 1;

FIG. 3 is a perspective view showing a second embodiment of the invention.

FIG. 4 is a perspective view showing the microwave oven of FIG. 3 set in a vertical type.

5 is a diagram for explaining an example of cooking using a microwave oven set to the state shown in FIG. 4. FIG.

FIG. 6 is a perspective view showing a third embodiment of the invention.

FIG. 7 is a perspective view showing a case where the heating chamber is set vertically in a third embodiment of the present invention.

FIG. 8 is a diagram for explaining a formula for deriving the minimum dimension of the heating chamber.

[Explanation of symbols]

5, 5a, 5b Heating chamber 6 Oven cooking heater

Claims (1)

[Claims] 1. A microwave oven having an oven function, characterized in that the frequency of high frequency waves for dielectric heating generated from high frequency generating means is set to 5.8 GHz.