JPS6364873B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high frequency heating device that connects a waveguide and a heating chamber through an opening.

Exciting a standing wave mode that mainly has a vertical electric field component in the heating chamber of a conventional high-frequency heating device is effective for heating devices such as microwave ovens because the standing wave mode is stably excited under various loads. This is a very important condition for improving the distribution of food heating equipment. However, as shown in Fig. 1, when high-frequency electromagnetic waves from a magnetron 1, which is a high-frequency oscillator, are coupled to a heating chamber 4 through an aperture 3 through a waveguide 2, the direction of an electric field 5 changes horizontally at the aperture 3, so the heating chamber 4, a standing wave mode with a vertical electric field could not be excited.

Furthermore, when the waveguide 2 and the heating chamber 4 are coupled by an antenna 6 as shown in FIG. 2, it is possible to excite a standing wave mode having a vertical electric field 5 in the heating chamber 4. However, with this structure, the tip of the antenna 6 protrudes into the heating chamber 4, which not only reduces the effective volume of the heating chamber 4, but also causes spark discharge in the high-frequency electric field if food particles get on the antenna 6. Furthermore, since the antenna 6 is required, the configuration becomes complicated and the cost increases.

The present invention solves the above-mentioned conventional drawbacks, and aims to excite a standing wave mode in the heating chamber and improve its distribution in a configuration in which the waveguide is coupled to the heating chamber through the opening of the waveguide.

Furthermore, by exciting a standing wave mode with a vertical electric field, it has stable distribution performance even when the load fluctuates, and the above standing wave mode can be used even if the load is placed in the center of the heating chamber. Another purpose is to be able to heat the central part and the central part equally.

In order to achieve the above object, the high-frequency heating device of the present invention sets the dimensions of the heating chamber so that the standing wave mode resonates, and matches the electric field direction and position of the standing wave mode with the electric field direction and position of the waveguide. By doing so, it is possible to excite a desired stable standing wave mode in the heating chamber by opening the waveguide and the heating chamber, to make the distribution uniform, and to construct a heating chamber with a large effective volume.

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

In FIG. 3, a door 7 is provided so that it can be opened and closed by a handle 8, and a control knob 9 can control the oscillation of a magnetron 1, which is a high frequency oscillator. Further, in this embodiment, since the air can be heated with gas or electricity and cooking can be done in an oven, a temperature control knob 10 is provided.

In FIG. 4, a device (not shown) for increasing the temperature using a gas burner, an electric heater, etc. is arranged behind the heating chamber 4, and hot air is heated by a fan (not shown).
The air enters the heating chamber 4 through the exhaust hole 11 through the intake hole 12.
I'm leaving. A pulley 14 is rotated through a belt 13 by a motor (not shown) at the bottom of the heating chamber. A permanent magnet 15 is provided on the pulley 14, and a turntable 16 provided in the heating chamber 4
Permanent magnets 17 that attract each other are provided inside, and the turntable 16 is rotated by the magnetic force of these magnets.
is rotated smoothly by rollers 18.

On the other hand, the dimensions of the heating chamber 4 are 1/λ ² = (m/2a) ² +
It is selected to satisfy the formula (n/2b) ² + (p/2c) ² . Here, a, b, c are the horizontal and vertical sides of the heating chamber 4,
is the height, and m, n, and p are the number of peaks of standing wave modes generated in each direction. λ indicates the wavelength of high frequency electromagnetic waves.

In the case of this example, if m = 3, n = 4, and p = 0, the c dimension is arbitrary and the relationship between a and b is as shown in Figure 5, so it can be anywhere on the 3, 4, 0 mode line. However, considering ease of use, the present invention has a=300mm,
b = approximately 308mm. Note that λ is approximately 122 mm.

FIG. 6 is a plan view schematically showing the electric field pattern and heating pattern of the 3.4.0 mode. In other words, the electric field is generated in the vertical direction and in the lateral direction (dimension a)
This shows that the electric field 19 changes, that is, three peaks of the electric field 19 occur, and four peaks of the electric field 19 occur in the vertical direction. Also, there is an electric field 19 next to each other's mountains.
Note that the directions are different.

Claims (1)

[Scope of Claims] 1 A heating chamber for heating an object to be heated and a high-frequency oscillator for generating high-frequency electromagnetic waves in a main body, the heating chamber and the high-frequency oscillator being coupled by a waveguide, and the heating chamber and the guiding The heating chamber is configured to be connected to the wave tube through an opening, and the heating chamber has dimensions in which a vertical electric field standing wave mode of the high-frequency electromagnetic wave occurs, and the direction and position of the electric field of the standing wave mode are determined based on the electric field of the waveguide. The high frequency heating device is configured such that the standing wave mode has an odd number of standing waves and an even number of standing waves in the vertical and horizontal directions when viewed from the top of the heating chamber. . 2. The high-frequency heating device according to claim 1, wherein a turntable for rotating a load is provided in the heating chamber. 3. The high-frequency heating device according to claim 1, wherein the opening is provided on the upper surface of the heating chamber. 4. The high-frequency heating device according to claim 3, wherein the length l of the aperture in the direction of propagation of radio waves is approximately half the wavelength within the waveguide. 5. The high-frequency heating device according to claim 1, wherein one end of the opening is configured to coincide with the terminal end of the waveguide. 6. Claim 3, wherein the opening has a short-circuit portion that is substantially parallel to the traveling direction of high-frequency electromagnetic waves in the waveguide, and a plurality of the openings are provided in the short-circuit portion.
The high-frequency heating device described in Section 1. 7. The high-frequency heating device according to claim 6, wherein a rib is appropriately provided approximately at the center of the short-circuit portion.