JPS5935160B2 - Power supply device in high frequency heating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-frequency heating device that uses a rotating antenna to supply high-frequency energy from a high-frequency oscillator to a heating chamber. The purpose of this is to prevent sparks caused by metal powder, etc. caused by rotational friction of the antenna.

Conventionally, this type of rotating antenna has a metal antenna connected to a drive shaft made of a dielectric material, and this drive shaft passes through a hole in the waveguide wall and connects to an external drive source such as a motor. The structure was such that

Therefore, when an electric heater or the like is used in conjunction with an open system, the temperature inside the heating chamber becomes extremely high, so the drive shaft must be made of a material with high heat resistance and low dielectric constant, such as ceramic. On the other hand, materials such as ceramics have high heat resistance, hardness, and friction coefficient, so there is a problem that metal powder accumulates inside the waveguide due to the force of the hole in the waveguide wall, which is the bearing part, while the antenna rotates. .

Even inside the waveguide, the electric field strength is high near the antenna, and there are problems such as when shavings such as metal powder fall and accumulate there, causing sparks and adversely affecting the characteristics.

Additionally, brazing has traditionally been used as a method of joining a metal antenna and a drive shaft made of ceramic, etc.
There was a problem in that the wax inserted between the ceramic and the antenna during the brazing process flowed out of the antenna, changing the effective dimensions of the antenna during actual use.

Therefore, the present invention solves the above-mentioned drawbacks of the conventional art with a simple structure, and one embodiment of the present invention will be described below with reference to the accompanying drawings. In Fig. 1, 1 is the main body of the high-frequency heating device, 2 is a heating chamber formed in the main body 1, 3 is a door that allows the front opening of the heating chamber 2 to be opened and closed, 4 is a high-frequency oscillator, and 5 is a high-frequency oscillator. 4 is a waveguide that transmits the high frequency energy generated to the joint with the heating chamber 2. 6 is a rotating antenna that supplies the high frequency energy transmitted through the waveguide 5 into the heating chamber, and is connected to the motor T that is the drive source. The drive shaft 8 is composed of a coupled drive shaft 8 made of a dielectric material such as ceramic, and a metallic antenna 9 connected to the drive shaft 8.

The drive shaft 8 and the metallic antenna 9 were connected with the end of the drive shaft 8 fitted into the end of the metallic antenna 9, as shown in FIG.

Note that the connection end surface portion 10 of the metal antenna 9 is formed to have a large diameter, and a groove portion 11 is provided between it and the end portion of the drive shaft 8.

Further, the drive shaft 8 passes through a hole 12 provided in the upper wall of the waveguide 5, and is rotatably supported by the hole 12.

On the other hand, the metallic antenna 9 passes through a hole 13 in the lower wall of the waveguide 5 and the upper wall of the heating chamber 2, and is supported by a bearing 14 made of a dielectric material such as ceramic. In the above configuration, most of the metal powder, etc. generated due to rotational friction between the drive shaft 8 and the hole 12 in the upper wall of the waveguide is contained in the groove 11 located directly below.
It accumulates inside.

Note that the inner diameter of the groove portion 11 can be made sufficiently smaller than the cutoff wavelength of the normally used frequency, so that radio waves will not enter this portion and will not cause sparks or adversely affect the characteristics. Furthermore, when brazing the joint between the metal antenna 9 and the drive shaft 8, wax will not flow out beyond the end surface of the antenna 9 due to capillary action as in the conventional method, and the effective dimensions of the antenna can be accurately obtained. .

In addition, by increasing the inner diameter of the antenna joint end surface, the outer diameter of the antenna tip becomes larger than the other parts, which allows the antenna itself to have broadband frequency characteristics, and is resistant to frequency fluctuations and variations. It can also exhibit stable antenna function. As explained above, the present invention provides a power feeding device using a highly reliable rotating antenna that has a simple configuration, has good dimensional accuracy and workability, does not cause sparks during operation, and has improved frequency characteristics. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a high-frequency heating device showing an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of the main part of the power supply device, and FIG. 3 is a cross-sectional view of the rotary antenna of the main part. 4...High frequency oscillator, 5... Waveguide,
6... Rotating antenna, 7... Motor,
8...Drive shaft, 9...Metallic antenna, 10...Joining end surface portion, 11...Groove portion.

Claims (1)

[Claims] 1. A heating chamber, a high-frequency oscillator that supplies high-frequency energy into the heating chamber, a waveguide that transmits the high-frequency electromagnetic waves oscillated by the high-frequency oscillator, and radiates the high-frequency electromagnetic waves transmitted by the waveguide within the heating chamber. The rotary antenna consists of a rotary drive shaft made of a low-loss material connected to a drive source, and a metal pipe connected to the rotary drive shaft, and the joint end surface of the metal pipe. A power supply device for a high-frequency heating device, characterized in that the large-diameter portion has a large diameter portion.