JPS6243313B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improving the uniformity of radio wave distribution in a high frequency heating device that uses a rotating antenna to radiate radio waves into a heating chamber.

Conventionally, in high-frequency heating devices that use a rotating antenna to supply radio waves into the heating chamber, in order to enhance the rotation effect of the rotating antenna, a method has been devised to radiate radio waves from the horizontal part of the antenna. Although improvements have been made so that the radio wave radiation from the horizontal portion is relatively larger than from the vertical portion, there is still the problem that the radio wave radiation from the horizontal portion changes depending on the rotation angle of the antenna and is unstable. Ta. For example, it has been found that when the horizontal part of the antenna faces toward the high-frequency oscillator when viewed from the center of the antenna's rotation axis, the amount of radio wave radiation is significantly lower than when it faces 180 degrees in the opposite direction.
This is presumed to be influenced by the direction in which the radio waves propagate, and even when looking at the operating point on the Rieke diagram (not shown), the standing wave ratio at this time becomes extremely high. I know that there is.

If the amount of radio wave radiation becomes uneven due to the angle of rotation of the antenna, the difference between strong and weak radio wave distribution within the heating chamber will naturally become apparent.
The heating was uneven, resulting in uneven heating.

The present invention solves the above-mentioned conventional drawbacks, and aims to eliminate non-uniformity in the amount of radio wave radiation from an antenna due to the angle of rotation of the antenna, and to improve the uneven distribution of radio waves.

In order to achieve the above object, in the present invention, the distance between the horizontal part of the rotating antenna and the wall surface of the heating chamber is made different on the high frequency oscillator side and the opposite side when viewed from the center of the rotation axis of the antenna. By increasing the amount of radio waves emitted when the antenna faces the high-frequency oscillator, the amount of radio waves emitted is reduced by increasing the amount of radio waves emitted when the antenna faces the high-frequency oscillator. This has the effect of improving the unevenness of the amount.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 1, 1 is a main body, and a heating chamber 2 is located inside the main body. Reference numeral 3 denotes a high frequency oscillator, and the radio waves oscillated by this are transmitted through a waveguide 4 and radiated into the heating chamber 2 by a rotating antenna 5.
The rotating antenna 5 consists of a vertical portion 6 serving as a rotation axis and a horizontal portion 7. A rotation drive shaft 8 made of a dielectric material is connected to the vertical portion 6.
passes through an opening provided in the upper wall of the waveguide 4 and is connected to the drive motor 9. Reference numeral 13 denotes a sealing plate that seals the coupling port through which the rotary antenna 5 penetrates the wall surface of the heating chamber 2, and simultaneously supports the rotary antenna on its axis. Reference numeral 10 denotes a saucer provided on the bottom wall of the heating chamber, on which the object to be heated is placed. Reference numeral 11 denotes a door that allows the front opening of the heating chamber 2 to be opened and closed.

In FIG. 2, on the high-frequency oscillator 3 side of the wall surface of the heating chamber 2 that overlaps with the waveguide 4, there is a distance A' between the horizontal portion 7 of the rotating antenna 5 and the wall surface of the heating chamber 2 in this part. The recessed portion 12 is provided so as to be larger than the distance A of the other portions.

FIG. 3 is a view seen from the top of the heating chamber 2, and the recessed portion 12 provided on the wall surface of the heating chamber 2 is formed when the horizontal portion 7 of the rotating antenna 5 faces the high-frequency oscillator 3. The distance between the horizontal portion 7 of the heating chamber 2 and the wall surface of the heating chamber 2 is formed to be larger than at other times.

The operation in the above configuration will be explained below.

The radio waves transmitted by the waveguide 4 are radiated into the heating chamber 2 by the rotating antenna 5, but if they are radiated from the vertical portion 6 of the rotating antenna 5, the rotation effect of the rotating antenna 5 cannot be obtained, so the heating room 2
By making the vertical portion 6 of the rotating antenna 5 as short as possible and adjusting the length of the horizontal portion 7 to an appropriate dimension for matching, the horizontal portion 7 can be made as short as possible.
We are trying to increase the amount of radio waves emitted from the Since the horizontal portion 7 of the rotating antenna 5 forms a strip line with the wall surface of the heating chamber 2, if the distance between them is small, it will be difficult for radio waves to be radiated from the rotating antenna 5, and conversely, if the distance between them is large, the radio waves will not be radiated. become more susceptible to Conventionally, the horizontal portion 7 of the rotating antenna 5
When the rotating antenna 5 faces the high-frequency oscillator 3, the standing wave ratio becomes extremely high, and the amount of radio wave radiation from the rotating antenna 5 decreases. However, in the structure of the present invention, the horizontal portion 7 of the rotating antenna 5 faces the high-frequency oscillator 3. Since the distance between the wall surface of the heating chamber 2 and the horizontal portion 7 of the rotating antenna 5 when facing the side is larger than at other times due to the recessed portion 12, the amount of radio wave radiation at this time is As a result, the non-uniformity of the amount of radio wave radiation due to the rotation angle of the rotary antenna 5 is improved, and the radio wave distribution within the heating chamber 2 is improved.

In this way, according to this embodiment, with a simple structure,
In particular, it eliminates the non-uniformity of the amount of radio wave radiation from the horizontal part of the rotating antenna 5 without increasing costs,
This has the effect that the radio wave distribution within the heating chamber 2 can be improved.

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

(1) By forming a recess in the wall of the heating chamber on the high-frequency oscillator side when viewed from the center of the rotation axis of the rotating antenna, the amount of radio wave radiation increases when the horizontal part of the rotating antenna faces the high-frequency oscillator side. , the radio wave distribution inside the heating chamber can be improved.

(2) By providing a similar recessed portion in any rotation angle direction of the rotating antenna, the amount of radio wave radiation from the rotating antenna changes in that portion.
Even if the amount of radio wave radiation from the rotating antenna decreases at a specific rotation angle due to effects other than the direction in which the radio waves travel (for example, the shape of the electric heater installed in the heating chamber), it will be compensated for. I can do things.

(3) By creating a partial recess in the heating chamber wall, a protrusion is created inside the waveguide, which functions in the same way as a post for adjusting the operating point normally installed inside the waveguide. By appropriately adjusting the dimensions of this recess, it is possible to improve the matching between the high frequency oscillator and the heating chamber.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a high-frequency heating device according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a main part of a rotating antenna portion of the same device, and FIG. 3 is a plan view of the main part. 2... Heating chamber, 3... High frequency oscillator, 4... Waveguide, 6... Vertical part of antenna, 7... Horizontal part of antenna, 13... Recessed part.

Claims (1)

[Scope of Claims] 1. A heating chamber, a high-frequency oscillator that supplies high-frequency waves into the heating chamber, a waveguide that transmits the radio waves oscillated by the high-frequency oscillator, and a radio wave that is transmitted by the waveguide. a rotating antenna that radiates radio waves into the heating chamber; the rotating antenna has a vertical portion and a horizontal portion with respect to the wall surface of the heating chamber to which the heating chamber is coupled, and the horizontal portion of the rotating antenna and the heating A high-frequency heating device configured such that the distance between the antenna and the wall of the chamber is uneven depending on the angle of rotation of the antenna. 2. Claim 1, wherein the distance between the horizontal portion of the rotary antenna on the side of the high-frequency oscillator and the wall surface of the heating chamber from the center of the rotation axis of the rotary antenna is larger than the distance on the opposite side. The high frequency heating device described. 3 A part of the wall surface of the heating chamber forming the waveguide is configured to protrude into the waveguide, and the distance between the wall surface of the heating chamber and the horizontal part of the antenna in this protruding portion is made larger than in other parts. A high frequency heating device according to claim 1.