JPH0130275B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a high-frequency heating device having means for uniformly heating an object to be heated, such as food, using microwaves.

Configuration of conventional example and its problems For example, the conventional high frequency heating device shown in FIG.
Microwaves emitted from a microwave oscillator 1 such as a magnetron are radiated through a waveguide 2 into a cavity 3 surrounded by a metal wall, and an antenna chamber 5 in the upper part of the cavity is separated by a partition plate 4. The radio wave form is regulated by a microwave stirring means 6 such as a rotating antenna or a stirrer, and a shielding plate 7 made of a metal body.
The radiation is distributed and radiated into a heating chamber 9 that houses an object to be heated 8 in the lower part of the cavity. However, in such a configuration, since the object to be heated 8 housed in the heating chamber 9 is located away from the shielding plate 7, the shielding effect of the shielding plate 7 is small, and the size of the cavity 3 and the oscillator 1
Depending on the conditions such as the oscillation frequency of the heated object 8
There is a problem that local overheating or underheating occurs. The conventional high-frequency heating device shown in FIG. 2 radiates microwaves emitted from a microwave oscillator 1 such as a magnetron through a waveguide 2 into a cavity 3 surrounded by a metal wall. Partition plate 4
A box-shaped metal shield called a rotating waveguide 10 is rotated in the antenna chamber 5 at the lower part of the cavity separated by the antenna chamber 5 to regulate the direction of the microwave and radiate it to the heating chamber 9 at the upper part of the cavity. However, with this configuration, depending on the size and shape of the object to be heated 8, there is a problem of non-uniform heating as in the conventional example shown in FIG. In other words, when the object to be heated 8 is rectangular and larger than the rotation range of the rotating waveguide 10, the area covered by the rotating waveguide 10 is circular, so the corner portion of the object to be heated 8 is has the problem of being overheated.

Purpose of the Invention The present invention solves the above-mentioned conventional drawbacks, and aims to provide a high-frequency heating device that has more uniform heating performance by devising the shape of the shielding plate and its positional relationship with respect to the heating chamber. shall be.

Structure of the Invention In order to achieve the above object, the high frequency heating device of the present invention includes a substantially rectangular parallelepiped cavity surrounded by a metal wall, a heating chamber made of a dielectric material, and a heating chamber in the lower part that stores the object to be heated. a partition plate separating the antenna room from the antenna room; a microwave oscillator; a waveguide for transmitting the microwaves generated by the oscillator; and a microwave coupling section provided on the bottom wall of the antenna room and connected to the waveguide. , a rotating antenna made of a metal body provided in the antenna room and rotating around the coupling portion, and a shielding plate made of a metal body provided between the partition plate and the rotary antenna, the shielding plate having a substantially rectangular shape. Each side of this rectangle is substantially parallel to each side of the bottom surface of the heating chamber, and supports made of metal bodies are provided near four corners of the rectangle of the shielding plate. is rectangular in shape, supports made of metal bodies are provided near four corners of the rectangle of the shielding plate, and the rectangular shape of the shielding plate is in a shape that is smaller than the rectangle of the bottom of the heating chamber. By being parallel to each other, there is no overheating of the corner portions when heating a large rectangular or square shaped object, and more uniform heating performance can be obtained.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 3, an operation panel 12 and a door 13 are attached to a main body 11 of the high-frequency heating device. A cross section of the main part of the main body 11 is as shown in FIG. In FIG. 4, a substantially rectangular parallelepiped cavity 3 surrounded by a metal body is separated by a dielectric partition plate 4 into a heating chamber 9 above the partition plate and an antenna chamber 5 below. This heating chamber 9 is a room for storing the object to be heated 8, and the antenna chamber 5 is a room for storing a structure for uniform heating. The partition plate 4 is made of a dielectric material with low dielectric loss and high heat resistance, such as borosilicate glass, silicon laminate,
It is fixed to the wall surface of the cavity 3 by a rail 14. A waveguide 2 equipped with a microwave oscillator 1 is provided on the lower outer side of the antenna room 5 and is coupled to the antenna room 5 through a coupling portion 15 provided at the center of the bottom wall of the antenna room 5 .
As shown in FIG. 5, this coupling part 15 consists of a fixed antenna 15-a formed by protruding a part of the wall surface of the waveguide 2 made of a metal body, and a coupling hole 15 provided in the bottom wall surface of the antenna chamber 5. -b are arranged coaxially. A rotary antenna 6 made of metal and having a rectangular plate shape is provided in the antenna room, and as shown in FIG. 5, it is held by a holding member 18 on a rotating shaft 17 attached to a motor 16. Rotationally driven by 16.
The rotating shaft 17 and the holding member 18 are made of a dielectric material with low dielectric loss such as polypropylene or fluorine resin, and the rotating shaft 17 has a hole provided at the center of the upper end of the fixed antenna 15-a with a slight clearance. It penetrates through. A shielding plate 7 made of a metal body is provided between the partition plate 4 and the rotary antenna 6. As shown in FIG. 5, this shielding plate 7 is provided so as to be almost in contact with the partition plate 4, and its planar shape is approximately rectangular as shown in FIG.
is parallel to each side of the base of . Furthermore, the shielding plate 7
As shown in FIG. 7, support portions 7-a made of metal are provided near the four corners of the rectangle.
Further, the shielding plate 7 has an opening 7-b for partially passing microwaves, and has a notch 7-c in a part of the rectangular side of the shielding plate, so that the antenna chamber 5 is screwed to the bottom wall of the The radius of rotation of the rotary antenna 6 is determined to such a length that, at a certain rotational position of the rotary antenna 6, the end of the rotary antenna 6 is exposed from the outer shape of the shielding plate, as shown in FIG. There is.

The operation of the above configuration will be explained below.
Microwaves emitted from the microwave oscillator 1 are supplied to the coupling section 15 through the waveguide 2. The coupling portion 15 is connected to the fixed antenna 15.
-a and the coupling hole 15-b act to couple the waveguide 2 and the antenna chamber 5 through coaxial coupling. The microwave propagated into the antenna room 5 is propagated along the rotating antenna 6 to the periphery of the antenna room 5, and is radiated into the heating chamber 9 through the partition plate 4. or,
Some of the microwaves are radiated into the heating chamber 9 through the opening 7-b provided in the shielding plate 7. Generally, in high-frequency heating devices such as microwave ovens, food or other objects to be heated are often heated by placing them in a glass container 19 as shown in Figure 8, and the shape of this container is also a square with a side of about 20 cm. are the most commonly used. In addition, it is generally preferable for the shape of the heating chamber to be approximately rectangular in terms of space saving and productivity, and when placing the above-mentioned square container in such a heating chamber, it is best to place it parallel to the rectangle on the bottom of the heating chamber. many. In this embodiment, a case is considered in which the object to be heated is placed in a square container as described above and heated. That is, since the shielding plate 7 has a substantially rectangular shape and is arranged in a position parallel to the rectangle on the bottom surface of the heating chamber, the entire bottom surface of the object to be heated placed in the square container as described above is covered by the rotating antenna 6. By appropriately providing the opening 7-b in the shielding plate 7, the distribution of heating on the bottom surface of the object to be heated can be adjusted. Furthermore, by providing the supporting portion 7-a made of a metal body as a microwave reflector near the rectangular corner of the shielding plate 7,
The microwave propagating along the rotating antenna 6 is prevented from propagating in the direction of the corner of the bottom surface of the heating chamber, thereby preventing overheating of the corner portion of the object to be heated.

As described above, according to this embodiment, when an object to be heated is placed in a square container commonly used in a high-frequency heating device such as a microwave oven and heated, the microwave propagates to the corner of the object. It weakens the heat, prevents overheating of the corners, and provides more uniform heating performance.
Further, since the shielding plate having the supporting portion is provided so as to be almost in contact with the partition plate, there is an effect that even if a heavy object to be heated is dropped onto the partition plate, the partition plate will not be damaged.

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

(1) When heating a rectangular or square shaped object, it prevents overheating of the corners of the object and provides more uniform heating performance.

(2) The strength of the partition plate on which heated objects are placed is improved, and the impact resistance is increased.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the main part of a conventional high-frequency heating device, FIG. 2 is a sectional view of the main part of another conventional high-frequency heating device, and FIG. 3 is a sectional view of the main part of a high-frequency heating device according to an embodiment of the present invention. A perspective view, FIG. 4 is a cross-sectional view of the main part of the same high-frequency heating device, FIG. 5 is an enlarged view of the main part of FIG. 4, and FIG.
The figure is a cross-sectional view of the main parts of the high-frequency heating device, with a part of the partition plate cut away, FIG. 7 is a perspective view of the shielding plate, which is a component of the high-frequency heating device, and FIG. 8 is a generally used container. FIG. DESCRIPTION OF SYMBOLS 1... Oscillator, 2... Waveguide, 3... Cavity, 4... Partition plate, 5... Antenna room, 6... Rotating antenna, 7... Shielding plate, 7-a... Support part, 7-b... Opening, 7-c …
Notch portion, 8... object to be heated, 9... heating chamber, 10...
Rotating waveguide, 11...Main body, 12...Operation panel, 1
3...door, 14...rail, 15...joint, 15-
a... Fixed antenna, 15-b... Connection hole, 16... Motor, 17... Rotating shaft, 18... Holding member, 19...
container.

Claims (1)

[Claims] 1. A substantially rectangular parallelepiped cavity surrounded by all-metal walls, a partition plate made of a dielectric material that separates this cavity into a heating chamber in the upper part for storing the object to be heated, and an antenna chamber in the lower part, and a microwave oscillator. , a waveguide for transmitting microwaves generated by the oscillator, a microwave coupling section provided on the bottom wall of the antenna room and connected to the waveguide, and a metal coupling section provided in the antenna room and rotating around the coupling section. a rotating antenna made of a body, and a shielding plate made of a metal body provided between the partition plate and the rotary antenna, and the shielding plate has a substantially rectangular shape, and each side of the rectangle corresponds to each side of the bottom surface of the heating chamber. A high-frequency heating device having a structure in which supporting portions made of a metal body are provided substantially parallel to the shielding plate and near four corners of the rectangular shape of the shielding plate.