JPS61156690A - High frequecy 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 [Field of Industrial Application] The present invention relates to a high-frequency heating device, and more particularly to a radio wave leakage prevention structure for an openable/closable door provided at the entrance of a heating chamber of a high-frequency heating device.

[Conventional technology]

Conventional high-frequency heating devices heat or cook food, which is an object to be heated, placed in a heating chamber using high-frequency energy supplied from a magnetron, which is a high-frequency radio wave generation source.

This heating chamber is equipped with a door that can be opened and closed, but there is a gap between the main body of the heating chamber and the door, and radio waves leak outside through this gap.

It is necessary to keep the amount of leakage below a permissible value in consideration of the shadow on the human body + 'll', and for this purpose a radio wave leakage prevention mechanism is provided mainly on the door surface.

A typical mechanism for preventing radio wave leakage in doors is the choke method, in which a choke structure with radio wave attenuation grooves is placed around the door periphery, and the radio wave passage formed by the heating chamber and the door is connected from the entrance to the groove. There is a method of setting the dimensions and the length of the groove to 1/4 of the radio wave wavelength used. According to this means, it is equivalent to short-circuiting the entrance of the radio wave path in terms of impedance, and has the advantage that leakage of radio waves can be prevented. In addition, as another mechanism to prevent radio wave leakage, periodic structures are placed in the radio wave path and choke structure.

A means for preventing leakage of radio waves by regulating the direction of radio wave propagation, or a means shown in Japanese Patent Publication No. 59-23435, that is, a means made of metal with a tip protruding in a direction parallel to the radio wave leakage path. A method has been proposed for suppressing radio wave leakage by arranging round triangular claw-like bodies and giving a specific relationship to the shape and dimension of the claw-like bodies. Furthermore, for example, in Japanese Patent Application Laid-Open No. 58-216388,
By arranging parallel line transmission lines having a T-branch section provided on either the main body or the door of the high-frequency heating device in the direction around the door via a gap, and making the bottom gap wider than the entrance gap of this branch line. , a means of sealing radio waves has been proposed.

[Problem that the invention seeks to solve]

It is difficult to make the door smaller.

[Means for solving problems]

A door is constructed by providing a substantially U-shaped metal groove (hereinafter referred to as a groove) with a partially L-shaped cross section and a corner portion on the periphery of the base body constituting the door in order to support the door base body. along with the opening of said groove.

An opening was made facing the opening peripheral overhanging wall (opening flange part or sash plate part) of the heating chamber, and a band-shaped metal was made inside this groove. A bent piece (hereinafter referred to as a bent piece) having a step similar in cross section to the cross section of the groove and a substantially T-shaped side surface is made such that its opening side coincides with the opening side of the groove, and this bending is performed. Pieces are provided periodically in the longitudinal direction of the groove.

In addition, by selecting the length from the entrance of the folded piece to the innermost part and to the stepped part under specific conditions, we can create a small door with less radio wave leakage, ensuring the safety and downsizing of the high-frequency heating device. It is something.

[Effect]

The corner part of the metal groove is close to the edge of the door body.

The step of the bent piece is divided into a deep part and a shallow part from the entrance to the wall surface, and cuts the fundamental wave component and harmonic component of each leaked radio wave.

〔Example〕

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

1 is a heating chamber for storing food; 2 is a cabinet surrounding the heating chamber 1; 6 is the door body, 4 is the satshu plate,
Reference numeral 5 denotes a flange portion surrounding the entire circumference of the opening of the heating chamber 1. Reference numeral 6 represents an operation and display portion for operating the high-frequency heating device, 7 represents a door handle, and 8 represents a viewing window.

A part of the side wall 9 of the heating chamber 1 is bent and has a flat flange part 5, and an upright sash plate 4 is provided on the extension part of the flange part 5.
It constitutes a heating chamber opening peripheral overhanging wall 5A that supports the door.

In front of the flange portion 5, radio wave sealing mechanism portions disposed on the peripheral edge of the door body 6 are arranged so as to face each other and partially contact each other. The Densaka seal mechanism is composed of a metal groove and a metal bent piece. That is, the door body B has an L-shaped corner part 10 in a part of its cross section.

There is a metal groove 11 that is generally U-shaped as a whole, and its outer surface 1
2 is flat dan.

The opening 13 faces the flange portion 5. Inside the groove 11 is a bent piece 14 made of a strip-shaped thin metal plate, the cross section of which has a similar shape to the groove 11.

The opening 15 is also in the same direction as the opening side of the groove 11.

They are arranged periodically in the longitudinal direction of the grooves 11. The ends 16 and 17 of the bent piece 14 are made horizontal, and a plastic cover 18 is attached to the two surfaces to prevent foreign matter from entering the groove. The side surface of the bent piece 14- is T-shaped as described later, and its dimensions, arrangement, etc. are appropriately selected to prevent leakage of radio waves from the gap between the cover 18 and the 7 flange portion 5.

In FIG. 6, the reason why the L-shaped corner part 10 is provided in the groove 11 is to bring the groove 11 into close contact with and support the door body 3, and to form a step in the folding piece 14 to be installed inside. The step was formed in the bent piece 14 by changing the depth of the bent part.

This is to cant the fundamental wave component and harmonic component of the leakage "xi," and the deep part of the bend from the entrance of the piece 14 to the wall surface 19 is the fundamental part, and the shallow part from the entrance to the wall surface 20 is the bend part. It is a high-tone component.

In FIG. 4, the folding piece 14 and the cover covering the opening of the groove 11 have been removed. In the figure, the depth is 64 kaku.

In the L-shaped corner metal groove 11 with a width of 20 strips, W=25+
a.

P=50 gourds, Ml, M2=5~10 pieces, horizontal end 2
A bent piece 14 having 1 to 24 and a one-step difference part 25,
They are arranged periodically with notches 26 in between. This bent piece 14 has a side wall surface approximately T-shaped in shape, one leg portion 27 having a width of 1 to 5, and a space portion 28 having a depth of 32+m at the deepest part for the fundamental wave and a shallower part. Set according to the harmonic you want to attenuate.

The amount of radio wave leakage under these setting conditions is 1.5 to 2.
With the door sealed through a simple thick plastic cover (1
It can be suppressed to 1 mW/ca or less, and the thickness of the door frame can be made thinner than before.

FIG. 5 is a sectional view of a mounting part showing another embodiment of the present invention, in which the same parts as described above are indicated by the same symbols. A U-shaped metal groove with L-shaped corners has an excellent radio wave sealing effect even in a structure where the opening is on the sash plate side and the side wall of the groove is in contact with the flange. This has the advantage of making the door thinner.

〔Effect of the invention〕

As described above, according to the present invention, the radio wave sealing mechanism in a high frequency heating device is formed by a U-shaped metal groove having an L-shaped corner and a substantially similar metal bent piece housed in this groove. Since the shape of the stepped material is such that the depth of the first bent portion is changed, it is possible to suppress the fundamental wave among the leakage radio waves and especially the harmonic waves with a high leakage level. Another feature of this simple radio wave leakage prevention mechanism is that the radio wave seal can be achieved with a narrow groove width, either the door frame or the thickness.

The point is that it can be made more compact by about 20III, which is about 25% compared to the conventional model.

[Brief explanation of the drawing]

1 is a perspective view showing the external appearance of a high-frequency heating device according to an embodiment of the present invention, FIG. 2 is a sectional view of the high-frequency heating device according to an embodiment of the present invention, and FIG. 6 is a main part of FIG. 2. FIG. 4 is an enlarged partial cross-sectional view showing the arrangement of grooves and bent pieces constituting the radio wave sealing mechanism of the present invention, and FIG. 5 is an enlarged sectional view of main parts in another embodiment. be. 1... Heating chamber. 3...Door body. 5A...Opening peripheral overhanging wall. 10... Corner part. 11...Groove. 14...Bent piece.

Claims (1)

[Claims] 1. A heating chamber for storing an object to be heated and a door that can be opened and closed at the opening of the heating chamber, the door body (3)
A substantially U-shaped metal groove ( 11
), the opening of the groove (11) is opened facing the opening peripheral overhanging wall (5A) of the heating chamber (1), and the inside of the groove (11) is made of a strip-shaped thin metal plate, and the cross section is the groove. A high frequency device characterized in that bent pieces (14) having a similar shape to (11) are arranged so that the opening side thereof is the opening side of the groove (11) and are provided periodically in the longitudinal direction of the groove (11). heating device. 2. The high-frequency heating device according to claim 1, wherein the depth of the groove formed by the bent piece (14) is set to 1/4 of the radio wave wavelength used, and 1/4 or less.