JPH0142600B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to improving the radio wave distribution of a high frequency heating device using a rotating radio wave radiator.

Conventional configurations and their problems A variety of methods have been proposed and implemented in the past in attempts to equalize the radio wave distribution within the heating chamber by rotating the radio wave emitter, but various methods have been proposed and implemented. The most effective method to have a stable effect even in heating chambers of different sizes and shapes is to rotate a radio wave emitter with a strong radio wave radiation direction, such as a waveguide, at the bottom of the heating chamber. I understand. Various rotating antennas, such as a rod-shaped antenna bent into an L-shape, etc., have been proposed and actually implemented, but the biggest problem with these cases is that it is difficult to make the radio wave radiation directional. It is very difficult, so even if you rotate the antenna,
The rotation effect was small, and a good radio wave distribution could not be obtained.

On the other hand, in the case of waveguides as shown in Figures 1 and 2, the radiation directivity is very strong, so the rotation effect is very good, but the strong directivity causes another problem. . That is, the electric field at the radiation opening 17 of the waveguide 9 is very strong, so in order to prevent this from directly hitting the food, the waveguide should be shaped as far as possible from the center of rotation, as shown in Figure 2. It is necessary to provide the radiation outlet far away, close to the edge of the heating chamber. However, when doing this, the radio wave distribution toward the ends of the heating chamber improves, but there is a problem in that the heating near the center becomes weaker.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and aims to provide a radio wave feeding structure for a rotating waveguide system that solves the heating unevenness in the central portion and has a good distribution of radio wave heating.

Structure of the Invention In order to achieve the above object, the present invention includes a heating chamber, a high-frequency oscillator, and a rotating radiator that radiates radio waves transmitted through a waveguide into the heating chamber, and the rotating radiator is simple. By combining the waveguide with the parallel plate line, the directivity of the waveguide is relaxed and the leakage of radio waves from the sides is actively prevented. By increasing it, the heating in the center becomes stronger,
This has the effect of making it possible to make the overall radio wave distribution uniform.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below based on the drawings.

In FIG. 3, numeral 1 denotes a main body with a heating chamber 2 therein, and numeral 3 denotes a door that allows the front opening of the heating chamber to be opened and closed.

In FIG. 4, 4 is a high frequency oscillator, and the radio waves oscillated by this are transmitted through a waveguide 5.
A rotating radiator 6 provided approximately in the center of the bottom of the heating chamber
is radiated into the heating chamber by The rotating radiator consists of a coaxial section 7 and a radiating section 8, as shown in a perspective external view in FIG. 5, and the radiating section 8 further consists of a waveguide section 9 and a parallel plate line section 10. The coaxial portion 7 is connected to a drive shaft 12 of a motor 11. Reference numeral 13 denotes a rail made of a low-loss dielectric material, on which the flange portion of the radiating section 8 slides and rotates, thereby maintaining a constant distance between the bottom wall of the heating chamber and the radiating section. 1
4 is a radio wave supply unit 1 in which a radiator rotating in a heating chamber is located;
5 and the heating section 16, and a food mounting table for placing food thereon, which is made of a heat-resistant dielectric material.

FIG. 6 shows another embodiment of the rotating radiator, in which the radiating section is constructed by sandwiching a parallel plate line section 10 between a waveguide section 9 and a waveguide section 9'.

The operation of the above configuration will be explained below.
The radio waves oscillated by the high-frequency oscillator 4 are transmitted through the waveguide 5, excited by the coaxial section 7 of the rotating radiator 6, enter the heating chamber, and then radiated into the heating chamber by the radiating section 8. However, since the first part of the radiation section is made up of a waveguide, the direction of the propagation width of the radio wave is very well controlled toward the open end of the waveguide.

However, at the tip of the waveguide, the side wall disappears and it becomes a parallel plate line, so some of the radio waves that have been controlled and transmitted in one direction are now radiated from the side. Increase the heating near the center of the food. Furthermore, the radio waves transmitted along the parallel plate line to the tip of the radiating section are radiated toward the top of the heating chamber from between the tip of the radiating section and the wall of the heating chamber, and are emitted by the side and top walls of the heating chamber. It is reflected and heats mainly the outer periphery of the food.

The position of the parallel plate line in the radiating part is
By changing as shown in the figure, it is possible to adjust the heating balance between the center and the outer periphery of the food.

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

(1) By configuring the radiating section with a combination of a waveguide section and a parallel plate line, it is possible to intensify the heating near the center of the heating chamber and improve the radio wave heating distribution throughout the heating chamber.

(2) By using parallel plate tracks, the weight of the entire radiator can be reduced, the friction between the rotating radiator and the rail during rotation can be reduced, and durability can be improved. .

(3) By using a parallel plate track at the tip of the rotating radiator, it is possible to move the center of gravity of the entire rotating radiator toward the coaxial section, and when the rotating radiator rotates along the rail. stability increases. (If the center of gravity is toward the tip of the radiator, the coaxial part will be lighter when relative to each other, so vibrations during rotation will cause the coaxial part to move up and down, making it unstable. This means that the coaxial part is not inserted into the waveguide. Since the dimensions change, the coupling between the waveguide and coax changes unstablely, resulting in unstable output.In this case, increasing the rail diameter can improve stability. However,
There is a problem in that as the diameter of the rail increases, it is necessary to increase the rotational torque of the motor. )

[Brief explanation of drawings]

Figure 1 is a sectional view of a product showing a conventional example, Figure 2 is an external perspective view showing the shape of a conventional rotating radiator, and Figure 3 is a cross-sectional view of a product showing a conventional example.
The figure is an external view of a product that is an embodiment of the present invention.
5 is an external perspective view showing the rotary radiator, and FIG. 6 is an external perspective view showing another embodiment of the present invention. 2... Heating chamber, 4... High frequency oscillator, 5... Waveguide, 6... Rotating radiator, 7... Coaxial section, 8...
Radiation part, 9... Waveguide part, 10... Parallel plate line part.

Claims (1)

[Claims] 1. A heating chamber, a high-frequency oscillator, and a waveguide that transmits the radio waves oscillated by the high-frequency oscillator.
A high-frequency heating device comprising: a rotating radiator that radiates radio waves transmitted by the waveguide into a heating chamber; the rotating radiator is configured by connecting a simplified waveguide and a parallel plate line in series. . 2. Claim 1 in which a radiation port is formed by connecting a parallel plate line to the open end of a simplified waveguide.
The high-frequency heating device described in Section 1.