JPH0156513B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a type of high-frequency heating device that uses a rotating antenna to supply radio waves into a heating chamber. The objective is to increase the effective size of the rotary antenna as much as possible, increase radio wave radiation from the horizontal portion of the rotary antenna, enhance the rotation effect of the rotary antenna, and improve the uniformity of the radio wave distribution.

When a rotary antenna is used in a high-frequency heating device that uses a conventional electric heater, the temperature inside the refrigerator becomes extremely high. material was used. However, there is a very high electric field near the coupling hole in the heating chamber, and since ceramic has a relatively high dielectric constant, the electric field tends to concentrate in this area. There was a problem with sparks on the surface.

In order to prevent this, conventionally, the cross section of the sealing plate was made concave to make the surface distance between the antenna and the end face of the heating chamber coupling hole as large as possible, and the plane of the sealing plate was moved from the heating chamber coupling hole to the heating chamber. I tried to face it and keep it away.

On the other hand, a rotating antenna has a roughly L-shape consisting of a vertical part and a horizontal part, but the radio waves radiated from the vertical part do not change even when the antenna rotates, so in order to improve the rotation effect of the antenna, It is necessary to increase the radio wave radiation from the horizontal part as much as possible. However, as the dimensions of the vertical part are shortened, the distance between the horizontal part and the top wall of the heating chamber becomes smaller, so the function as a transmission line is strengthened between the top wall of the heating chamber and the horizontal part, and radio waves are transmitted from the horizontal part as well. It becomes less radiated. Therefore, a certain amount of space is required between the horizontal part and the upper wall of the heating chamber, but in order to maintain this space and suppress radio wave radiation from the vertical part, the vertical part of the antenna is set as shown in Figure 1. From the point where it enters the heating chamber, connect it to the horizontal part with as large an radius as possible. Alternatively, an inclined portion may be provided between the horizontal portion and the vertical portion. Also, from the experimental results, it was found that the distribution is better if the vertical and horizontal parts of the antenna are connected with as large an radius as possible.

However, in this case, the antenna cannot be rounded or sloped until it passes through the bearing hole in the sealing plate that swings the joint opening of the heating chamber, so the flat surface of the sealing plate must be heated to prevent sparks as described above. When lowered toward the indoor surface, only the vertical part of the antenna remains, making it difficult to suppress radio wave radiation from this part. Also, as mentioned above, it is preferable to provide a certain amount of radius at the intersection of the vertical and horizontal portions of the antenna, but if we add the distance to the bearing surface of the sealing plate to this radius, the antenna The dimension that protrudes into the heating chamber increases, and the effective height inside the heating chamber decreases accordingly. The present invention solves these problems and provides a structure that maximizes the effective height of the heating chamber and also provides good distribution performance.

An embodiment of the present invention will be described below with reference to the drawings.
In Fig. 1, 1 is a main body, inside which is a heating chamber 2.
There is. The radio waves oscillated by the high-frequency oscillator 3 pass through the waveguide 4 and are irradiated into the heating chamber by the rotating antenna 5. The rotating antenna 5 consists of a vertical part 6 and a horizontal part 7, the intersections of which are connected by R. The vertical portion of the rotary antenna is rotatably supported by a bearing hole provided in a sealing plate 9 that seals a coupling port 8 between the heating chamber and the antenna.

The sealing plate 9 is lowered to avoid the high electric field area near the coupling port of the heating chamber, and the rotating antenna is required to improve the radio wave distribution after passing through the bearing hole of the sealing plate. It connects to the horizontal part via the R part. The above is an explanation of the conventional example of the sealing plate and the antenna part. In FIG. 2, the sealing plate 9
Since the antenna is shaped to protrude into the waveguide beyond the coupling port 8 of the heating chamber, the antenna can be connected to the horizontal part with a large radius immediately after entering the heating chamber from the waveguide. Therefore, since there is virtually no vertical portion of the antenna inside the heating chamber, the radiation of radio waves from the vertical portion is extremely small, and most of the radiation is from the horizontal portion, so that the rotation effect of the rotating antenna is very good.

Even with this shape, the sealing plate not only avoids the part where the electric field is concentrated at the coupling port of the heating chamber as in the conventional case, but also allows the lower surface of the sealing plate to penetrate into the waveguide more than the upper wall surface of the heating chamber. Food scraps from cooking,
It has the advantage that the surface is less likely to be contaminated by oil or the like. When the sealing plate becomes dirty, it becomes hot and carbonizes, causing problems such as sparks. Also, if an antenna with the shape shown in Figure 2 is attached to a conventional downward-hanging mouth plate, the effective height inside the heating chamber will be reduced because the entire antenna will be lowered into the heating chamber, but according to the present invention, the effective height inside the heating chamber will be reduced. There is no such thing.

As described above, according to the present invention, the structure is simple, the rotation effect of the rotary antenna is good, and by doing so, the effective height of the heating chamber is not reduced, and sparks and the like are less likely to occur.

In addition, since the vertical part of the rotating antenna is not placed inside the heating chamber, the radio wave radiation from the vertical part is kept to a minimum, and the amount of radio waves radiated from the horizontal part is correspondingly increased, so that the rotation effect of the rotating antenna can be fully utilized. It is possible to improve the radio wave distribution within the heating chamber.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a high-frequency heating device showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the essential parts thereof. 2... Heating chamber, 3... High frequency oscillator, 4... Waveguide,
5... Rotating antenna, 8... Heating chamber coupling port, 9... Sealing plate.

Claims (1)

[Claims] 1 a heating chamber, a high frequency oscillator, a waveguide, a rotating antenna that couples the waveguide and the heating chamber in a high frequency manner, a coupling port of the rotating antenna to the heating chamber is sealed, and the rotating The rotary antenna has a sealing plate that serves as a rotational bearing for the antenna, and the sealing plate has a bearing portion protruding into the waveguide so that a vertical portion of the rotating antenna is not substantially exposed inside the heating chamber. High frequency heating equipment.