JPS62122090A - Radio frequency heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a high-frequency heating device, and particularly relates to an improvement of a high-frequency heating device in which a rotating waveguide is provided in a heating chamber.

(Technical background of the invention and its problems) Some microwave ovens (high-frequency heating devices) have a rotating waveguide installed inside the heating Wa as shown in FIG.

Conventionally, such a rotating waveguide has a structure in which it is formed into a container shape from a metal such as an aluminum plate and has an excitation opening C in its bottom wall, as shown in FIG. This rotating waveguide is placed in the upper part of the heating chamber a, and connected to a motor e (drive m) provided outside the heating chamber a to generate microwaves from the magnetron (generator) f. The structure is designed to accept

In such a microwave oven, in addition to operating the motor e, by operating the magnetron f, the microwave Q... generated by the magnetron f enters the rotating waveguide through the opening and rotates. It is excited from the excitation aperture C while reflecting off the peripheral wall of the waveguide.

However, since the conventional rotating waveguide has a regular shape as shown in Figure 8, the reflected microwave q...
There is a problem that . is not efficiently excited from the excitation aperture C, resulting in a large output loss. For this reason, microwave ovens using rotating waveguides were unable to produce the desired output. Moreover, the output loss not only prevents high output, but also turns the output loss into heat and makes the rotating waveguide high temperature, which causes the shaft h for supporting the rotating waveguide to be However, it has the disadvantage that it must be constructed from high-quality materials such as Teflon, which is highly heat-resistant.

(Purpose of the invention) This invention was made by focusing on the above-mentioned circumstances.
The purpose is to provide a high-frequency heating device that can efficiently excite high-frequency waves entering a rotating waveguide.

[Summary of the Invention] This invention significantly improves the reflection efficiency, which was conventionally considered to be poor, by providing a rotating waveguide with a reflection section that reflects the supplied high frequency waves and concentrates them on the excitation aperture. This is intended to reduce output loss.

[Embodiments of the invention]

The present invention will be explained below based on a first embodiment shown in FIGS. 1 to 3. FIG. 3 shows a microwave oven (high-frequency heating device) to which the present invention is applied, in which 1 is a main body, 2 is a heating chamber provided in the main body 1, and 3 is an excitation chamber provided on the upper wall of the heating chamber 2. The opening 4 is a waveguide with a magnetron (ffi device) 5 connected to one end. A waveguide 4 is installed on the upper wall of the heating chamber 2, and the outlet side of the waveguide 4 is connected to the opening 3 to heat the microwave (high frequency) 11 oscillated from the magnetron 5. It is designed so that it can be supplied to chamber 2.

On the other hand, 6 is a rotating waveguide. The structure of this rotating waveguide 6 is shown in FIG. Here, if the rotating waveguide 6 is explained, 7 is a waveguide main body. The waveguide body 7 is made of, for example, a metallic material or resin,
It is constructed in the shape of a container with a rectangular opening. In addition, in the case of resin molding, metal plating is applied to the surface. A fixing hole 8 is provided on the bottom wall of the waveguide body 7 at a position centered from the center to one end, and a circular excitation opening 9 is provided at the other end opposite to this. It is provided.

Then, a peripheral wall portion 7a near this excitation opening 9.

A reflecting section 10 is provided at each of the sections 7a. Each reflective portion 10.10 is configured by protruding the peripheral wall portions 7a, 7a outward in a substantially triangular shape. The angles and surface shapes of these irregularly shaped triangular parts 10a, 10a are set so as to reflect the microwaves 11 entering the rotating waveguide main body 7 and concentrate them on the excitation aperture 9. The structure is such that as many microwaves 11 as possible are excited without loss. The rotating waveguide 6 is placed in the upper part of the heating chamber 2 with its opening facing the opening 3, so that it can receive the microwaves emitted from the opening 3. Of course, the opening of the rotating waveguide 6 is large enough to accommodate the entire opening 3.

On the other hand, 12 is a motor installed on the outer surface of the upper wall of the waveguide 4, directly above the opening 3. The output part of this motor 12 and the hole 8 of the rotating waveguide 6 are connected via a shaft 13 made of a heat-resistant dielectric material such as Teflon, as shown in FIG. The rotary waveguide 6 can be rotated eccentrically around the shirt I 13 using the driving source as a driving source. However, 14 indicates a fixing screw for fixing the rotating waveguide 6 and the shaft 13.

In FIG. 3, reference numeral 15 denotes a partition plate made of a material that is transparent to radio waves and is provided so as to cover the periphery of the rotating waveguide 6 to protect the rotating waveguide 6.

Next, the operation of the microwave oven configured as described above will be explained. Now, there are 16 things to be cooked (things to be heated) in the heating chamber 2.
and operates the operating section of the microwave oven (not shown).

This causes the magnetron 5 and motor 12 to operate. Microwaves are then oscillated from the magnetron 5 and guided into the rotating waveguide 6 through the waveguide 4° opening 3.

The microwave then travels through the rotating waveguide 6 while being reflected and is irradiated into the heating element 2 from the excitation aperture 9. Here, conventionally, the reflection efficiency is poor and the desired output is not produced. It is pointed out that

However, according to the present invention, the peripheral wall portions 7a, 7a near the excitation opening 9 are provided with triangular portions 10a.

A reflecting section 10.10 consisting of a shaped part 10a is provided to absorb the microwaves 11 that have entered the rotating waveguide 6 from reflection.
・is concentrated on the excitation aperture 9. This means that the microwave 11 passing near the excitation aperture 9, which causes loss, is also guided to the excitation aperture 9, and it can be seen that high output with significantly reduced loss can be obtained due to the improvement in reflection efficiency. .

In this way, the high frequency waves entering the rotating waveguide 6 can be efficiently excited. As a result, the food 16 can be heated efficiently. Moreover, since the output loss is significantly reduced, the rotating waveguide 6 does not need to be heated to a high temperature as in the conventional case, and therefore the shaft 13 supporting the rotating waveguide 6 can be made of inexpensive material.

Note that the present invention is not limited to the first embodiment described above, but the second embodiment shown in FIG.

A third embodiment shown in FIGS. 5 and 6 may be used.

That is, in the second embodiment shown in FIG. 4, the peripheral wall portions 7a, 7a near the excitation opening 9 are formed in a semicircular shape, and the reflecting portion 10.10 is formed from the semicircular portion 20.20 (unshaped portion). It is designed to consist of

Further, in the third embodiment shown in FIGS. 5 and 6, a reflecting plate 21 formed by cutting and raising a part of the bottom surface is provided on the inner bottom surface near the excitation aperture 9, and the third embodiment shown in FIGS. As in the example, a reflecting section 10 is configured to concentrate microwaves onto the excitation aperture 9 by reflection. Of course, instead of using cut-outs, a reflector plate 21 made of a separate member is provided to reflect the reflection part 1.
It may be set to 0.

In FIGS. 4 to 6, the same components as those in the first embodiment are given the same reference numerals, and their explanations are omitted.

〔Effect of the invention〕

As explained above, according to the present invention, high frequency waves entering the rotating waveguide can be efficiently excited. As a result, output loss can be reduced and high output can be obtained accordingly. Moreover, since the output loss is reduced, there is an advantage that the member supporting the rotating waveguide can be made of inexpensive material.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIGS. 1 to 3 show a first embodiment of the present invention,
FIG. 1 is a perspective view showing the main reflecting section together with a rotating waveguide, FIG. 2 is a cross-sectional view showing the installation state of the rotating waveguide, and FIG. 3 is a cross-sectional view showing a high-frequency heating device. Fig. 4 is a perspective view showing the main parts of the second embodiment of the invention, Fig. 5 is a perspective view showing the main parts of the third embodiment of the invention, and Fig. 6 is an enlarged view of the area around the reflector. 7 is a sectional view showing a conventional high-frequency heating device using a rotating waveguide, and FIG. 8 is a perspective view showing the rotating waveguide. 2... Heating chamber, 6... Rotating waveguide, 9... Excitation opening, 10a, 20.21... Triangular portion, semicircular portion. Reflector (reflector). Figure 1 Figure 2 Figure 3

Claims (3)

[Claims] (1) A rotating waveguide configured in a vessel shape and having an excitation opening formed in the bottom wall is provided in the heating chamber, and high frequency waves supplied to the opening of the rotating waveguide are transmitted together with the rotating waveguide. The high frequency heating device is characterized in that the heating chamber is irradiated from a rotating excitation aperture, characterized in that the rotating waveguide is provided with a reflecting portion that reflects the supplied high frequency and concentrates it on the excitation aperture. High frequency heating equipment. (2) The high-frequency heating device according to claim 1, wherein the reflecting portion has a peripheral wall portion in the vicinity of the excitation opening that is irregularly shaped. (3) The high-frequency heating device according to claim 1, wherein the reflecting portion includes a reflecting plate provided on the inner bottom surface in the vicinity of the excitation opening.