JPS60198087A - High 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 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 width is 2 earthquakes ± 0.5 mm'.

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

Therefore, rather than providing a slit (slit) in the circumferential wall of the radio maze as in the conventional example, the present invention constructs a portion of the circumferential wall of the V41 wave maze from a plurality of metal pieces spaced sufficiently apart. By applying specific conditions to these metal pieces. It is designed to act as an independent matching element for radio waves that efficiently guide leaked radio waves into the radio maze.

Its purpose is to have a simple structure, easy assembly, and small door dimensions. There is a need to obtain a high frequency heating device with a good space factor.

Next is the high frequency heating device of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS-1 FIG. 1 is a cross-sectional view of a main part showing an embodiment of a 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 periphery of the outer box B extends the metal plate constituting the outer box holder, and also serves as a satsush 3a surrounding 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 transparent to radio waves is press-fitted into the entrance lower a of the wave maze 7, and a door cover 8 made of a dielectric material transparent to radio waves is press-fitted to the outer periphery of the door front plate 6. Reference numeral 9 denotes a transparent outer window cover provided on the outside of the viewing window 11 consisting of a large number of small holes, and 12 represents a transparent inner window 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 B, which periodically form narrow microstrip lines facing the sash 6a.

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

The operation of the present invention is shown in FIGS. 2 and 1.

Explain the effect. The gap dimension B between adjacent metal pieces 10 is larger than the entrance dimension A of the radio wave maze 70.

Metal piece 1 for leakage radio waves including the next mode and second harmonic.
The electric field component generated between the 0 tip and the peripheral edge 5a of the door rear plate 50 (which allows leakage radio waves to enter the radio maze 7) increases, and the electric field component (which allows leakage radio waves to enter the radio maze 7) between the metal pieces 10 increases. (Unable to enter the radio maze Z) will be reduced. That is, the metal piece 10 functions as a kind of matching element that efficiently guides leaked radio waves into the radio wave maze 7 and is independent of each other in terms of radio waves.

Also, since the gap dimension B is smaller than the inside, it becomes a cutoff for the fundamental wave and second harmonic that enter the radio maze Z, and prevents radio waves from passing through the gap B and leaking to the outside. There is. Since the overhang dimension T1 is made smaller than the diameter, there is no series resonance with respect to the fundamental wave and the second harmonic, so a large amount of single frequency current does not flow through the metal piece 10.

As stated in the cited Utility Model Application Publication No. 54-130642, the slit part of the conventional slit choke generates heat.
The dog's shortcomings are eliminated. Furthermore, the gap dimension B is larger than the distance between the metal plates between the satshu 3a and the metal piece 10.

By setting the width W to 1, the periodic microstrip lines formed between 0 and 3a and 100 become radio wave independent of each other, and each microstrip line can transmit only one wave in its transmission mode. Therefore, it is possible to realize a significantly low leakage radio wave θ·k.

According to the experiment, the distance between the metal plate 3a and the metal piece 10 [1] is 6.5 mm + the width W or IQ of the metal piece 10
mm, overhang dimension II is 10 mm + gap dimension B is 10
Cutting, entrance dimension A is 6 mm + gear knob between door rear plate 5 and flange 2 is 1 mm, high frequency output! 5oow
The maximum leakage power at a distance of 5cm from the aircraft is 0.03u+WA# under the conditions of using wavelength 122mm and water load 275rnIV! (Sub.

In the next example, Sho 54-130642, it is about 0 with radio wave absorption interest.
．． 2vnW/cJ), which was found to be sufficiently practical.

As described above, according to the present invention, the outermost edge of the door front plate forming the wall of the radio maze is composed of a plurality of metal pieces that are mutually independent in terms of radio waves, and the xanossy is placed opposite to the metal pieces. Narrow microstrip lines are formed periodically, and the width of the gap between the metal pieces is made larger than the distance between the two.
Since it is possible to significantly reduce leakage radio waves, shortwave absorbing materials are uncomfortable, and since part of the door front panel itself is a periodic structure, no additional parts are required, so the number of parts is small and the structure is simple. It is possible to provide a high-frequency heating device 6 that is easy to assemble, has a small door outer diameter = j method, and has a good space factor, and the effects of implementing it are impressive.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a high-frequency heating device K of the present invention, and FIG. 2 is a perspective view of the main part for explaining the action of a metal piece 10. 1...Heating chamber 2...Flange 6a...Sash 4.Door 5...Door rear plate 6...Door front plate 7...Radio wave maze 10...Metal Single hanger Hitachi Thermal Appliances Co., Ltd. Figure 1 @ Figure 2

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 door (4) that opens and closes the opening.
), a radio maze (7) is constructed around the periphery. The labyrinth (7) consists of a door rear plate (5) that makes plane contact with the flange (2), and a door front plate (6) whose outermost periphery consists of a plurality of metal pieces (10) that are radio-independent from each other. surrounded by metal pieces (10), a narrow microstrithop line is periodically formed by facing the metal piece (10), and the gap size of the metal piece (10) is
b) A high-frequency heating device characterized in that the width (b) is larger than the distance (1)) between the sassoche (3a) and the metal piece (10).