JPS60207281A - High frequency heating device - 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 The present invention relates to an improvement in the radio wave leakage prevention structure of a door provided at the entrance of a heating chamber of a high-frequency heating device so as to be openable and closable.

A radio maze is installed around the door of the high-frequency heating device.

There is a proposal in Utility Model Application Publication No. 54-130642 to provide slits in the partition plates that make up this radio maze (choke).
In this conventional example, the slit (width 2 mm ±0.5 mm) is used.

Since it cannot be said that the radio wave sealing effect is sufficient with only 10 pinches or less, radio wave absorbing material is added to the outer wall of the partition plate. As a result, the number of parts increases, the structure becomes complicated, the ease of assembly is poor, and the outer dimensions of the door become large, resulting in a high-frequency heating device with a poor space factor.

Therefore, rather than providing a slit (slit) in the peripheral wall of the radio maze as in the conventional example, the present invention constructs the peripheral wall of the radio maze from a plurality of metal pieces spaced sufficiently apart. By applying specific conditions to a piece of metal,
They are designed to act as mutually independent matching elements in terms of radio waves that efficiently guide leaked radio waves into the radio maze.

The purpose is to obtain a high-frequency heating device that has a simple structure, good assemblability, small door external dimensions, good space factor, and durability.

Next, the structure and operation of the high frequency heating device of the present invention will be explained with reference to the drawings.

FIG. 1 is a sectional view of essential parts of an embodiment of the high-frequency heating device of the present invention. 1 is a heating chamber into which an object to be heated is placed; 2 is a flange surrounding the entire opening of the heating chamber 1; 3 is the outer box that houses heating chamber 1.

The front periphery of the outer case slot also serves as a sash 3a that extends the metal plate constituting the outer case 3 and surrounds the door 4.

Reference numeral 5 denotes a door rear plate that is in plane contact with the flange 2, and the door rear plate 5 and the door front plate 6 forming the exterior form a radio wave maze 7. Heating chamber 1. Flange 2. The satchel 3a, the door rear plate 5, and the door front plate 6 are each made of a metal plate.

A maze cover 7b made of a dielectric material that transmits radio waves is press-fitted into the entrance lower a of the radio wave maze 7, and a door cover 8 made of a dielectric material is press-fitted onto the outer periphery of the door front plate O. Reference numeral 9 denotes a transparent window cover provided outside the viewing window 11 consisting of numerous small holes;
is a transparent window 7 cover provided on the heating chamber 1 side of the viewing window 11. Reference numeral 10 denotes a plurality of metal pieces periodically extending from the outermost edge of the door front plate 6 and facing the sash 62.

The main part perspective views of the maze cover 7b and the door cover 8 are shown in FIG. 6 and FIG. 4, respectively, and as shown in FIG.
supports the metal plate 10 from the outer and inner surfaces, and therefore plays the role of mechanically reinforcing the metal piece 10. Incidentally, only one of them, for example, the maze cover b, may be used.

The maze cover 7b has a convex f'fls protruding from its outer surface.
7ba is fixed to the peripheral end 5a of the door rear plate 50, and a convex portion 7bb protruding toward the inner surface is adjacent to the inner surface of the metal piece 10.

The metal pieces 10 are prevented from being deformed by mechanical shocks from the outside of the door 4.The door cover 8, which has an angular cross section, has a stone bar 83 protruding from its inner surface inserted into the gap between the metal pieces 10. , closely fixed to the outer surface of the metal piece 10,
This prevents deformation of the metal piece 10 due to external mechanical shock. The door cover 8 not only serves as a reinforcing material for the metal piece 10, but also serves to fix the window outer cover 9 to the front surface of the door front plate B.

FIG. 2 is an explanatory diagram for showing the action of the metal piece 100.

The gap size B between adjacent metal pieces 10 is determined by radio wave maze 7.
It is larger than the inlet dimension A of. Therefore, for leakage radio waves including higher-order modes and harmonics, an electric field component between the tip of the metal piece 10 and the peripheral edge 5a of the door rear plate 50 ((Leakage radio waves can enter into the radio maze Z) increases, and the electric field component generated between the metal pieces 1G (which prevents leakage radio waves from entering the Oki wave maze Z) decreases.In other words, the metal pieces 10 generate radio waves that efficiently guide leakage radio waves into the radio wave maze 7. They function as a kind of matching element that are mutually independent.

According to the experiment, the width W of the metal piece 10 is 10 mm + the overhang dimension H is 10 groups, the gap dimension B is 10 mm, and the input is 1-1.
At a distance of 5 crn from the aircraft, the maximum leakage power is 0.6 mm, with one cap between the door rear plate 5 and flange 2, high frequency output of 500 W, and water load of 275 mm. 03mWAJ (Conventional example, 1987-13064)
2 was found to be as low as about 0.2 mw/Aa for the radio wave absorbing material, which is sufficient for practical use.

As described above, a plurality of metal pieces are provided on the outermost edge of the door front plate, which is the peripheral wall of the radio maze facing the doorway and the sash, and the gap size between adjacent metal pieces is determined from the entrance dimension of the radio maze. In addition to suppressing small leakage waves with a thick comb, the labyrinth cover is press-fitted and fixed between the peripheral edge of the door rear panel and the metal piece, so the metal piece is mechanically reinforced and has a long-term radio wave leakage prevention effect. You can hold it. In addition, we can provide a Zl 1-frequency heating device that has a large radio wave leakage prevention effect, does not require radio wave absorbing material, has a small number of parts, has a simple structure, is easy to assemble, has a small door external dimension, and has a good 1 space factor. There is a dog-like effect.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the main parts of the high-frequency heating device of the present invention, and FIG.
The figure is a perspective view of the main part for explaining the action of the metal piece 10,
FIG. 3 is a perspective view of the main part of the maze cover 7b, and FIG. 4 is a perspective view of the main part of the door cover 80). 1... Heating chamber 2 Flange 3a... Sash 4 Door 5... Door rear plate 5a Peripheral end of door rear plate 5 6...
Door front plate 7... Radio maze applicant Hitachi Thermal Appliances Co., Ltd.

Claims (1)

[Claims] The opening of the heating chamber (1) is equipped with a flange (2) that surrounds the entire periphery of the opening, and a satush (3a) made of a metal plate that protrudes in front of the flange (2).
), and the labyrinth (7) consists of a door rear plate (5) that makes plane contact with the flange (2), and a plurality of metal pieces ( whose outermost edges face the satush (6a)). The gap dimension (B) between adjacent metal pieces (10) is made wider than the entrance dimension (A) of the radio maze (7), and the radio maze ( 7) entrance (7a
) and the metal piece (
10) A high-frequency heating device characterized in that it is press-fitted and fixed between.