JPS6127878B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a high-frequency heating device, such as a microwave oven, which guides high-frequency waves output from a high-frequency oscillator into a heating chamber through a waveguide. Generally, in microwave ovens and the like, the electric field in the center of the heating chamber is made stronger than in the surrounding area in order to improve the quality of the food. By the way, as shown in FIG. 1, in the case of a structure in which a high frequency wave outputted from a magnetron (high frequency oscillator) 1 is guided into a heating chamber 3 via a waveguide 2,
A high frequency reception port 5 is formed in the center of the ceiling plate 4 of the heating chamber 3, and the electric field at the center of the heating chamber 3 is reduced by radiating high frequency waves guided through the waveguide 2 from the high frequency reception port 5 into the heating chamber 3. I was trying to make it stronger.
However, in the case of the above conventional configuration,
Directivity of radio waves occurs depending on the size of the high frequency reception port 5, and unnecessary radiation of high frequencies often increases.
There was a problem in that the electric field at the center of the heating chamber 3 could not be made sufficiently strong. Therefore, it is not possible to adjust the distribution of the high frequency waves radiated into the heating chamber 3 to a good condition, which tends to cause uneven heating of the food placed in the heating chamber 3, resulting in poor quality of the finished food. It was difficult to stabilize the cooking time, and the cooking time could not be shortened. This invention was made based on the above circumstances, and its purpose is to make the electric field in the center of the heating chamber sufficiently strong by reducing unnecessary high-frequency radiation, thereby stabilizing the finished state of food. At the same time, it is possible to shorten cooking time and improve cooking performance.In addition, it is possible to reliably support the opening cover that closes the high-frequency reception port, and it is possible to set the impedance of the heating chamber in a position where there is less unnecessary radiation. The object of the present invention is to provide a high-frequency heating device that can be moved. The present invention will be explained below based on each embodiment. 2 to 10 show a first embodiment of the present invention. In FIG. 2, 11 is, for example, the main body of a microwave oven. A heating chamber 12 is formed within the main body 11, and a magnetron (high frequency oscillator) 13 is housed therein. A turntable 14 is provided at the bottom of the heating chamber 12, and this turntable 14 is driven by a drive motor 1 attached to the lower surface of the bottom plate 15 of the heating chamber 12.
6. Furthermore, a rectangular high-frequency reception opening 18 is formed in the center of the ceiling plate 17 of the heating chamber 12 . moreover,
A waveguide 19 is attached to the upper surface of the ceiling plate 17 of the heating chamber 12. A magnetron 13 is attached to the base end of this waveguide 19. Further, the tip of the waveguide 19 is connected to the high frequency reception port 18 . On the other hand, the lower part of the high-frequency reception port 18 is closed by an aperture cover 20 made of, for example, a silicon plate, and on the lower surface of this aperture cover 20, as shown in FIG. ) 21, 21 are provided. These reflecting plates 21, 21 are each formed into a substantially L-shape by a metal plate, and are arranged facing each other so as to protrude inward from the heating chamber 12 at the high-frequency receiving port 18, and are screwed together. It is attached to the ceiling plate 17 together with the opening cover 20 by means of, for example, the opening cover 20. In this case, the reflecting plates 21, 21 are respectively arranged along the edges of a pair of opposing openings in the high-frequency reception port 18. Furthermore, as shown in FIGS. 4 and 5, projecting pieces 32 are cut and formed on the surface of the reflecting plates 21, 21 that are connected to the opening cover 20, and these projecting pieces 32... As shown in FIG. 6, it is attached so as to protrude into the high frequency reception port 18. Therefore, in the case of the above configuration, the high frequency wave output from the magnetron 13 is guided through the waveguide 19 and supplied into the heating chamber 12 from the high frequency reception port 18. In this case, most of the high-frequency waves that have passed through the high-frequency reception port 18, which were previously supplied into the heating chamber 12 as unnecessary radiation, are reflected by the pair of reflection plates 21, 21 and are directed to the center of the heating chamber 12. radiated. Therefore, unnecessary radiation supplied into the heating chamber 12 can be reduced compared to the conventional case. The applicant has proposed a configuration in which a pair of reflecting plates 21, 21 are provided on the lower surface of the opening cover 20 below the high-frequency reception port 18 (configuration of the present invention) as shown in FIG. This was confirmed in the following first and second experiments using configurations in which the reflectors 21 and 21 are not provided on the lower surface of the opening cover 20 below the opening cover 18 (conventional configuration), respectively. The first experiment was carried out in a heating chamber 12 as shown in FIG.
Five containers 22a to 22 each containing 100 c.c. of water are placed on the inner turntable (diameter L) 14.
e, the magnetron 13 is operated for 2 minutes in this state, and the temperature rise value of the water in each container 22a to 22e is measured to investigate the temperature distribution in the heating chamber 12. . Also,
In the second experiment, as shown in FIG. 9, 15 frozen Shumai 23... were placed on the turntable 14, and the magnetron 13 was operated to measure the thawing state of each frozen Shumai 23... It is. The experimental results of the first experiment are shown in Table 1, and the experimental results of the second experiment are shown in Table 2.

【table】

[Table] As is clear from Table 1 above, the temperature rise value of the water in the container 22c located at the center of the heating chamber 12 is significantly higher in the structure of the present invention than in the conventional structure. It can be seen that the electric field at the center of the heating chamber 12 has become stronger. Furthermore, the second
As shown in the table, compared to the conventional structure, the structure of the present invention has a significantly smaller temperature difference between each of the shumai 23 placed on the turntable 14, and the temperature difference between the foods, etc. in the heating chamber 12 is significantly smaller. It can be seen that it is heated evenly. Therefore, by providing the reflection plates 21, 21 in the high frequency reception port 18,
The high frequency supplied into the heating chamber 12 from the high frequency reception port 18 has less unnecessary radiation than before.
The electric field at the center of the heating chamber 12 can be strengthened. Therefore, the electric field distribution within the heating chamber 12 is adjusted to a favorable state, so that uneven heating of food, etc. placed within the heating chamber 12 can be reduced, and as a result, the finished state of the food can be improved. Not only can it be stabilized, but also the cooking time can be shortened. Further, an aperture cover 20 is provided on the reflectors 21, 21.
The protruding pieces 32 are cut and raised on the joint surface side, and the opening cover 20 can be held down by these protruding pieces 32, so that the opening cover 20 can be supported reliably. Further, each protruding piece 32 of the reflecting plates 21, 21 is connected to the high frequency reception port 1.
Since it is installed in a protruding state within 8,
The impedance of the heating chamber 12 can be moved to a position with less unnecessary radiation by each protruding piece 32. In addition, in Figure 10, the high frequency frequency is 2450M.
Hz, water load is 2000 c.c., A is the conventional configuration, B is the protruding piece 32.
The high frequency reception port 18 is connected to the reflection plates 21, 21 provided with...
This shows the experimental results (impedance) when the As is clear from Fig. 10, the unnecessary radiation ranges from 43〓 (conventional) to 35〓 (invention).
Therefore, a damping effect of about 6 to 8 can be obtained. Furthermore, since the impedance of the heating chamber 12 differs depending on the size of the heating chamber, for example, as shown in FIG.
As shown in FIG. 12, projecting pieces 33... or 34... matched to each impedance are attached to reflectors 35, 36.
It may also be configured such that it is provided in Further, FIGS. 13 and 14 show a second embodiment of the invention. This is heating chamber 1
An SC enamel board (ceiling protection board) 41 is provided along the ceiling board 17 on the top of the SC enamel board 4.
An opening 42 is formed in a portion facing the high frequency reception port 18 of No. 1, and a pair of reflecting plates (reflecting portions) are formed in this opening 42 by cutting and forming.
43, 43 are provided to protrude inward of the heating chamber 12. The SC enamel plate 41 automatically decomposes and removes oil stains and the like using the heat in the heating chamber 12 during heating. In addition, in Figure 13, 4
4 and 45 are heaters disposed above and below the heating chamber 12, respectively. Therefore, the same experiment as the first experiment was conducted using the above configuration. The results of this experiment are shown in the third
Shown in the table.

[Table] As is clear from Table 3, even if the SC enamel plate 41 has a pair of reflective plates 43, 43 protruding from it, the container 22c placed in the center of the heating chamber 12 It can be seen that the temperature rise value of the water inside the heating chamber 12 is significantly higher than that of the conventional structure, and that the electric field at the center of the heating chamber 12 is stronger. Therefore, even with such a configuration, the same effects as in the first embodiment can be obtained. Further, in the case of the above structure, by providing the reflectors 43, 43 on the SC enamel plate 41, it is possible to make it more difficult for food particles etc. to adhere to the opening cover 20 compared to the structure of the conventional structure. Therefore, it is possible to reduce the risk that food scraps and the like adhering to the opening cover 20 are carbonized during heating and sparks are generated when high frequency waves are irradiated, causing the opening cover 20 to burn out, as in the conventional case. In addition,
Of course, the reflecting plates 43, 43 may be provided separately from the SC enamel plate 41 as shown in FIG. It should be noted that the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention. As explained above, according to the present invention, the reflection section that reflects high frequency waves is formed by a pair of reflection plates that are spaced apart from each other, and these reflection plates are connected to the rectangular high frequency reception port formed in the heating chamber. Since these are placed along the edges of a pair of opposing openings and protrude toward the inside of the heating chamber, out of the high frequency supplied into the heating chamber from the high frequency reception port, conventionally unnecessary radiation is absorbed into the heating chamber. Most of the food that was being fed can be reflected by the reflector and radiated to the center of the heating chamber, making the electric field in the center of the heating chamber strong enough to stabilize the finished state of the food and shorten the cooking time. It is possible to shorten the cooking time and improve cooking performance. Furthermore, since each reflecting plate is provided with a protruding piece that protrudes into the high-frequency receiving port and supports the opening cover of the high-frequency receiving port, each projecting piece can reliably support the opening cover that closes the high-frequency receiving port. At the same time, the impedance of the heating chamber can be moved to a position with less unnecessary radiation by each protruding piece.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing a conventional example, and FIGS. 2 to 10 show a first embodiment of the present invention.
Fig. 2 is a vertical cross-sectional view showing the overall schematic configuration, Fig. 3 is a perspective view showing the reflector, Fig. 4 is a plan view of the same, and Fig. 5
The figure is a side view, Figure 6 is a vertical cross-sectional view of the main part showing how the reflector is attached, Figure 7 is a perspective view of the reflector used in the first and second experiments, and Figure 8 is the same side view. FIG. 9 is a plan view showing the arrangement of containers on the turntable in the first experiment, FIG. 9 is a plan view showing the arrangement of shumai on the turntable in the second experiment, and FIG. 10 is a Rieke diagram showing Rieke characteristics. , FIGS. 11 and 12 are plan views showing different modifications of the first embodiment, and FIGS. 13 and 14 are respectively plan views showing different modifications of the first embodiment.
The figures show the second embodiment; FIG. 13 is a vertical cross-sectional view showing the overall schematic configuration, FIG. 14 is a perspective view showing the SC enamel plate, and FIG. 15 is a modification of the second embodiment. It is a perspective view showing an example. 12... Heating chamber, 13... Magnetron (high frequency oscillator), 18... High frequency reception port, 19... Waveguide, 20... Opening cover, 21, 43... Reflection plate (reflection part), 32, 33 , 34...Protruding piece.

Claims (1)

[Claims] 1. A rectangular high-frequency receiving port is formed in the heating chamber,
In a high-frequency heating device in which high-frequency waves outputted from a high-frequency oscillator are guided through a waveguide and supplied into the heating chamber from the high-frequency receiving port, a reflecting portion that reflects the high-frequency waves is formed by a pair of spaced apart reflecting plates arranged opposite to each other. These reflecting plates are respectively arranged along the edges of a pair of opposing openings in the high-frequency reception port and protrude toward the inside of the heating chamber. A high-frequency heating device characterized in that a protruding piece is formed that protrudes into the reception port and supports an opening cover of the high-frequency reception port. 2. The reflective part is disposed in the heating chamber along the ceiling plate of the heating chamber, and is formed on a ceiling protection plate that automatically decomposes and removes oil stains and the like during heating. The high frequency heating device according to scope 1.