JPS6243317B2 - - Google Patents

Description

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

Conventional structure and its problems Conventionally, there is a turntable method in which the food table is rotated as a method to equalize the distribution of radio waves in the heating chamber of high-frequency heating equipment, but in this conventional method, radio waves are transmitted from the top of the heating chamber. Because it has a structure that emits radio waves, the distance from the source of the radio waves to the food is long, so the radio waves are reflected off the heating chamber wall many times before being absorbed by the food, and are attenuated to some extent before being absorbed by the food. Therefore, it has the disadvantage of poor heating efficiency and the disadvantage that the heating in the center of the heating chamber is inevitably weak.

Furthermore, depending on the product, there are models that cannot use a turntable, and in that case, it is necessary to equalize the radio wave distribution using a method other than a turntable. It is extremely difficult to achieve uniform radio wave distribution using any method other than a turntable, so it was impossible to create exactly the same heating chambers.

Purpose of the Invention The present invention solves the above-mentioned conventional drawbacks, and is a high-frequency heating device that has good heating efficiency and radio wave distribution, can use a shared heating chamber even for models that do not use a turntable, and is capable of comprehensive rationalization. The purpose is to provide.

Structure of the Invention In order to achieve the above object, the present invention includes a heating chamber, a high-frequency oscillator, a waveguide for transmitting radio waves oscillated by the high-frequency oscillator, and a heating chamber that connects the waveguide and the heating chamber to the bottom wall of the heating chamber. It has an antenna that couples at the center, and a coupling hole that couples the heating chamber with a waveguide provided at a point 1/2 wavelength or more away from the antenna, and a dielectric material is provided at the tip of the heating chamber of the antenna. The antenna is connected to a turntable, and the antenna is rotated. Radio waves are directly radiated from the rotating shaft and coupling hole of the turntable, so the distance to the food is short and the heating efficiency is high. good.
Also, if the model does not use a turntable, remove the food table at the tip of the dipole antenna,
If a horizontal antenna is attached instead, it becomes a rotating antenna, so the basic oven structure can be completely shared, which has the effect of eliminating rationalization.

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

In FIG. 1, 1 is a main body, and a heating chamber 2 is located inside. A front opening of the heating chamber provided for taking food in and out can be opened and closed by a door 3.

Reference numeral 4 denotes a high frequency oscillator, and the radio waves oscillated thereby are transmitted through a waveguide 5 and radiated into the heating chamber from the bottom of the heating chamber through a coupling hole 19 between the waveguide and the heating chamber and a dipole antenna 6.

The dipole antenna 6 is provided approximately at the center of the bottom wall of the heating chamber, and the coupling hole 19 is provided at a position approximately 1/2 wavelength or more from the dipole antenna 6 toward the rear of the heating chamber.

Reference numeral 7 denotes a food table connected to the tip of the dipole antenna 6 inside the heating chamber, and is made of a dielectric material and is detachably connected to the dipole antenna in order to facilitate cleaning of the bottom wall of the heating chamber.

Reference numeral 8 denotes a rotary drive shaft made of a dielectric material connected to the inner end surface of the waveguide of the dipole antenna, which passes through the waveguide wall and is connected to the pulley 9, and is driven by the motor 11 via the belt 10 and pulley 9'. It is driven to rotate, thereby rotating the dipole antenna and the food table.

The pulley 9 is provided with a plurality of rollers 12 in order to receive the loads of the dipole antenna and the food table in the positive direction. The end face of the dipole antenna 6 connected to the food table 7 is designed to prevent the food table from melting due to local electric field concentration at the tip of the antenna.
Its diameter is about λ/4 or more, which is larger than the other parts. This also provides a more stable mechanical connection with the food platform.

Reference numeral 13 denotes a sealing plate for sealing the coupling port with the dipole antenna provided on the bottom wall of the heating chamber, which is made of a dielectric material and also serves as a rotation bearing for the dipole antenna.

Reference numeral 20 denotes a waveguide for guiding the radio waves emitted into the heating chamber from the coupling hole 19 so that they are more efficiently absorbed by the food, and has a shape that widens from the coupling hole toward the food. Reference numeral 21 denotes a lid made of a dielectric material, which prevents food gas and the like from entering the waveguide from this portion.

On the other hand, a plurality of reflective surfaces 14 and 15 are provided on the bottom wall of the heating chamber on the opposite side of the coupling hole 19 when viewed from the dipole antenna.
and 16 are provided, thereby efficiently reflecting the radio waves radiated in the horizontal direction from the dipole antenna toward the food.

FIG. 2 shows an example of uniformizing the radio wave distribution using the same heating chamber as in FIG. 1 but without using a turntable. A fixed food mounting table 18 is provided at the bottom of the heating chamber in place of the rotary food mounting table.
At the tip of the dipole antenna, there is a horizontal part 1 of the antenna that constitutes a rotating antenna instead of a food table.
7 is connected. In the case of Figure 1, the radio wave emission position is fixed and the food itself rotates, whereas in Figure 2, the position of the food is fixed,
Instead, it has a structure in which the radio wave emission position rotates,
All other structures except the shape of the food mounting table and antenna can be made completely the same.

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

(1) Since radio waves are emitted from below the rotating food table, the food is close to the radio wave radiation source, and heating efficiency is therefore high.

(2) Since the dipole antenna is connected to the center of the turntable, it is easy to strengthen the radio wave distribution in the center, which was difficult in the past.

(3) Since the tip of the dipole antenna connected to the turntable has a large diameter of approximately λ/4 or more, it is possible to prevent abnormal electric field concentration at the tip of the antenna, and furthermore, it is possible to prevent abnormal electric field concentration in the center. It is possible to strengthen the radio wave distribution over a wider range.

(4) Since another power feeding opening is provided approximately 1/2 wavelength or more toward the rear of the heating chamber from the antenna installed approximately in the center of the heating chamber, feeding power from the antenna alone will result in The center of the bottom is heated too strongly compared to the top, but the radio waves from this other feeding port heat the surrounding area, which is difficult to heat with the antenna, and some of the radio waves are not directly absorbed and are transferred to the side walls and top wall of the heating chamber. Since it is reflected and absorbed from the top of the food, the top and bottom of the food can be heated evenly and in a well-balanced manner.

Especially if the food table is a fixed type, if you install another power supply port at the rear of the heating chamber, in the case of a small load, food is rarely placed directly above it, and in most cases, the radio waves from this Most of the heat is not directly absorbed by the food, but is reflected from the side and top walls of the heating chamber and then absorbed from the top of the food.

(5) Since power is supplied from below the turntable,
There is no need to provide any openings for power supply on the upper wall of the heating chamber, and the interior of the heating chamber feels tidy and is therefore easy to clean.

(6) It is possible to change from a turntable type to a rotating antenna type simply by changing the food table and antenna, so the design for change is easy, and parts can be standardized and shared. Comprehensive rationalization will be undertaken.

(7) Since it serves as both the rotary drive shaft of the turntable and the antenna, the structure is simple and costs can be reduced.

(8) Since a plurality of reflective surfaces are provided on the bottom wall of the heating chamber on the opposite side of the coupling hole 19 when viewed from the antenna, the radio waves radiated horizontally from the antenna are efficiently reflected toward the food, increasing heating efficiency. It can be improved.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a high frequency heating device showing an embodiment of the present invention, and FIG. 2 is a side sectional view of the same device in the case of using an antenna system. 1... Main body, 2... Heating chamber, 4... High frequency oscillator, 5... Waveguide, 6... Antenna, 7... Food mounting table, 14, 15, 16... Reflective surface, 19...
Coupling port, 20... Waveguide.

Claims (1)

[Scope of Claims] 1. A heating chamber for storing food, a high-frequency oscillator for feeding high-frequency waves into the heating chamber, and a waveguide for transmitting radio waves oscillated by the high-frequency oscillator.
an antenna that connects the waveguide and the heating chamber at approximately the center of the bottom wall of the heating chamber; a food mounting table made of a dielectric material connected to the tip of the antenna; A high-frequency heating device configured to include a coupling hole for coupling a heating chamber to a waveguide provided at a point separated by a wavelength of /2 or more, and to rotate the antenna. 2. The high-frequency heating device according to claim 1, wherein a waveguide having a shape that widens toward the end is provided around the heating chamber side of the coupling hole between the heating chamber and the waveguide. 3. The high-frequency heating device according to claim 1, wherein a plurality of different reflecting surfaces are provided on the bottom wall of the heating chamber on the side opposite to the coupling hole when viewed from the antenna. 4. The high-frequency heating device according to claim 1, wherein the coupling hole between the heating chamber and the waveguide is provided behind the antenna when viewed from the front of the heating chamber.