JPH0424636Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] Even if the lid attached to the microwave oven container body rattles, the invention can magnetically attach the lid to the rim of the opening of the container body to prevent radio waves. This invention relates to a leakage radio wave absorber that prevents leakage and has a good absorption effect on a radio wave absorber.

[Conventional technology]

Conventionally, a leakage radio wave absorbing material formed by mixing soft ferrite such as manganese zinc ferrite or nickel zinc ferrite into synthetic resin was used between the container body and the lid of a microwave oven, for example at the opening edge of the container body. It is used. However, the leakage radio wave absorbing material tends to have a reduced effect of absorbing leakage radio waves when the lid is spaced apart from the opening rim of the microwave oven container body and a gap exists. for example,
The microwave oven lid gets fatigued during its use.
If a gap of 2 mm or more is created, for example, due to looseness in the hinge that attaches the lid, or due to various foreign objects adhering to or intervening between the microwave oven container body and the lid, radio waves may be emitted. The absorption effect of the absorbing material is reduced, and radio wave leakage occurs.
The present invention eliminates the absorption effect of the leakage radio wave absorbing material provided on the opening edge or inside the lid even if a gap is generated at the opening edge of the container main body of a conventional microwave oven due to rattling of the lid or the presence of foreign objects. The aim is to solve this problem by providing a means to ensure this.

[Means for solving problems]

The leakage radio wave absorber of the present invention that solves the above problem is arranged on at least one of the inner surface of the lid or the rim of the opening of the main body, which opens and closes by contacting the rim of the opening in the container main body of the microwave oven, and the entire body is arranged on the rim of the opening of the microwave oven. is an annular sheet member having approximately the same shape as the annular sheet member, and one of the inner peripheral part or the outer peripheral part of this annular sheet member is made of a radio wave absorbing material made by dispersing and mixing soft ferrite in a synthetic resin,
The other is made into a permanent magnet that is magnetized after hard ferrite is dispersed and mixed into a synthetic resin, and the soft ferrite mixed part is formed in such a way that the surface of the hard ferrite mixed part is positioned slightly behind the surface of the soft ferrite mixed part. It is characterized by being integrally molded with a hard ferrite mixed part.

[Effect]

The leakage radio wave absorber of the present invention is provided with a hard ferrite-containing part on the inner or outer periphery of an annular radio wave absorbing material and magnetized, and the surface of the hard ferrite-containing part is slightly smaller than the surface of the soft ferrite-containing part. Since it is positioned on the rear side, it is possible to adsorb the lid to the rim of the opening and close the lid and the rim of the opening in a tight state with a soft ferrite-containing part having radio wave absorption ability interposed therebetween. Radio waves that are about to leak from between the lid and the edge of the opening can be captured and attenuated by the soft ferrite mixed part. In addition, even if the lid is installed loosely, the lid itself is bent, or there is a foreign object between the lid and the edge of the opening, the magnetized hard ferrite-containing part will still hold the lid. is sucked in, so the gap between the lid and the rim of the opening is made as small as possible, and since the soft ferrite-containing part protrudes further forward than the hard ferrite-containing part, it is sure that it will come into contact with the lid or the opening rim. It becomes a soft ferrite-containing part that has radio wave absorption ability. Therefore, radio waves attempting to exit the microwave oven must pass through the soft ferrite-containing portion, and leakage of radio waves is effectively prevented.

〔Example〕

The details of the present invention will be explained based on further illustrated embodiments. As shown in FIG. 2, the leakage radio wave absorber according to the present invention shown in FIG. The lid 3 is magnetically attached to the edge 2 to maintain the absorption effect of the radio wave absorber. 4 in the figure is a leakage radio wave absorber according to the present invention, and as shown in the figure, its overall shape is the opening edge 2 of the container body 1.
It is an annular sheet member that has approximately the same shape as , and its thickness is set to be extremely small compared to its width. A hard ferrite mixed part (hereinafter referred to as hard ferrite part), which is made by mixing hard ferrite into a synthetic resin and then magnetizing it to form a permanent magnet, is located on either the inner or outer peripheral part of this annular sheet member. On the other hand, there is a soft ferrite-containing part (hereinafter referred to as the soft ferrite part) in which soft ferrite is mixed into a synthetic resin to form a radio wave absorbing material, and the hard ferrite part is located on the facing lid and opening. Like a normal adsorption magnet, so that the edges can be attracted
The magnetization direction is the thickness direction of the hard ferrite portion. The hard ferrite portion magnetically attaches the lid 3 to the container body 1, and the soft ferrite portion prevents the absorption of leakage radio waves. In the illustrated example, a hard ferrite portion 5 is provided on the inner periphery, and a soft ferrite portion 6 is provided on the outer periphery.
is positioned. Both parts are integrally molded by dispersing each hard ferrite material or soft ferrite material in a synthetic resin and integrally molding, for example, biaxial molding. As the hard ferrite used here, strontium ferrite, barium ferrite, etc. are used, and as the soft ferrite, nickel zinc ferrite, manganese zinc ferrite, magnesium zinc ferrite, etc. are used. The synthetic resins mixed with these ferrites include polypropylene, polyamide, polyphenylene sulfide, vinyl chloride, etc.
The ferrite is dispersed in this synthetic resin, and is preferably integrally molded by biaxial molding or the like. As shown in FIG.
The surface of the soft ferrite part 6 located on the outer periphery is set to be located slightly behind the surface of the soft ferrite part 6, so that even if the lid 3 is separated from the container body 1 due to rattling or the like, the hard The lid 3 is magnetically attached to the opening edge 2 of the container body 1 by the magnetic force of the ferrite part 5, and both parts are in contact with the surface of the soft ferrite part 6, which protrudes slightly toward the lid side than the surface of the hard ferrite part 5. Closely contact. Therefore, radio waves leaking from inside the microwave oven container main body 1 are always absorbed and attenuated by the soft ferrite portion 6 to prevent radio wave leakage. It goes without saying that, instead of having the hard ferrite portion 5 on the inner circumferential portion and the soft ferrite portion 6 on the outer circumferential portion as in the embodiment, it is also possible to use a state in which these positions are reversed.

[Effect of idea]

As described above, in the leakage radio wave absorber of the present invention, a hard ferrite-containing part is provided on the inner or outer periphery of the annular radio wave absorbing material, and the hard ferrite-containing part is magnetized, and the surface of the hard ferrite-containing part is replaced with a soft ferrite-containing part. Since the lid is positioned slightly behind the surface of the opening, the lid can be adsorbed to the rim of the opening and the lid and the rim of the opening can be closed in close contact with the soft ferrite-containing part having radio wave absorption ability interposed therebetween. This is possible, and the soft ferrite-containing portion can catch and attenuate radio waves that are about to leak from between the lid and the edge of the opening. Also, if the lid is not installed properly,
Even if the lid itself is bent or there is a foreign object between the lid and the edge of the opening, the magnetized hard ferrite mixture will attract the lid.
The gap between the lid and the rim of the opening is made as small as possible,
Moreover, since the soft ferrite mixed portion protrudes more to the front than the hard ferrite mixed portion, it is always the soft ferrite mixed portion that has radio wave absorbing ability that comes into contact with the lid or the edge of the opening. Therefore, radio waves attempting to exit the microwave oven must pass through the soft ferrite-containing portion, and radio wave leakage can be effectively prevented. In addition, the hard ferrite-containing part, which is a permanent magnet, is arranged adjacent to the widthwise side of the soft ferrite-containing part, and the facing lid or opening edge is magnetized to allow absorption. The emitted magnetic flux is mainly directed in the thickness direction of the hard ferrite mixed part, and it is possible to prevent the adjacent soft ferrite mixed part from being magnetically saturated as much as possible, and to prevent the radio wave absorption function of the soft ferrite mixed part from being impaired. It is considered. Furthermore, since this leakage radio wave absorber is in the form of a sheet and has a small thickness, it can pass through the width direction of the sheet, that is, the gap formed by the lid and the opening edge from the container side entrance toward the outside of the container. Although it has excellent radio wave attenuation ability for radio waves that move, the radio wave attenuation ability in the thickness direction is not so great. Therefore, even if a radio wave attenuation groove is formed on the inner surface of the lid or on the edge of the opening that comes into contact with the surface of the soft ferrite-containing part, the radio waves that pass through the soft ferrite-containing part in the thickness direction and enter the chi-yoke groove. The radio wave attenuation effect by the chiyoke grooves can be utilized to the fullest without causing much attenuation. In addition, both the soft ferrite mixed part and the hard ferrite mixed part use synthetic resin as a binder, and both are integrally molded by biaxial molding, etc., so the soft ferrite mixed part and the hard ferrite mixed part can be handled as one unit. It is easy to handle and suitable for mass production, and since the coefficient of thermal expansion of the soft ferrite mixed part and the hard ferrite mixed part is almost the same, there is a difference in thermal expansion between the soft ferrite mixed part and the hard ferrite mixed part. There are no cracks etc.

[Brief explanation of drawings]

Fig. 1 is an explanatory perspective view of the leakage radio wave absorber according to the present invention, Fig. 2 is an explanatory perspective view of the device installed in a microwave oven, and Fig. 3 is a cross-sectional explanatory view of the device installed in the microwave oven. . 1... Container body, 2... Opening rim, 3... Lid,
4... leakage radio wave absorber, 5... hard ferrite section, 6... soft ferrite section.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. The entirety of at least one of the inner surface of the lid that opens and closes in contact with the opening rim of the microwave oven container body or the opening rim of the main body has substantially the same shape as the opening rim. One of the inner and outer circumferential parts of this annular sheet member is made of a radio wave absorbing material made by dispersing and mixing soft ferrite in a synthetic resin, and the other part is made of a radio wave absorbing material made by dispersing and mixing hard ferrite into a synthetic resin and then magnetized. This microwave oven is manufactured by molding a soft ferrite-containing part and a hard ferrite-containing part integrally in such a manner that the surface of the hard ferrite-containing part is positioned slightly behind the surface of the soft ferrite-containing part. A leakage radio wave absorber in the mouth. 2. The leakage radio wave absorber according to claim 1, which comprises hard ferrite placed on the inner periphery of the annular sheet member.