JPH0424637Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention prevents radio waves by magnetically attaching the lid to the opening edge of the container body even if the lid attached to the microwave oven container body becomes loose. The present invention relates to a leakage radio wave absorber that prevents leakage of radio waves and improves the absorption effect of the radio wave absorber.

[Conventional technology]

Conventionally, a leakage radio wave absorbing material made 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 around the opening edge of the container body. It is used. However, if there is a gap between the lid and the opening rim of the container body of the microwave oven, the leakage radio wave absorbing material tends to have a reduced effect of absorbing leakage radio waves. For example, the lid of a microwave oven may become fatigued during use, causing the hinge that attaches the lid to rattle, or various foreign objects may become stuck between the microwave oven container body and the lid. As a result, if a gap of, for example, 2 mm or more is created, the absorption effect of the radio wave 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 present invention that achieves the above object has an overall shape that is disposed on at least one of the inner surface of the lid that opens and closes by contacting the opening rim of the microwave oven container body or the opening rim of the main body, and the overall shape is substantially the same as the opening rim. The annular sheet has a soft ferrite-containing part as a main body, which is a radio wave absorbing material formed by dispersing and mixing soft ferrite in a synthetic resin, and a part of the soft ferrite-containing part, With the soft ferrite mixed part remaining on the surface side, a hard ferrite mixed part made by dispersing and mixing hard ferrite in a synthetic resin is formed in a buried state, and the soft ferrite mixed part and the hard ferrite mixed part are integrally molded. In addition, the hard ferrite mixed portion is magnetized to become a permanent magnet.

[Effect]

This leakage radio wave absorber with such a structure has a hard ferrite mixed part as a magnetized permanent magnet in a part of the annular sheet-shaped radio wave absorbing material, and a soft ferrite mixed part as a radio wave absorbing material remains on the surface. Since the cap is buried in a state where it is buried, it is possible to adsorb the lid toward the edge of the opening and close the lid and the edge of the opening in close contact with the soft ferrite-containing part that has radio wave absorption ability in between. Therefore, the soft ferrite mixed portion can reliably catch and attenuate radio waves that are about to leak from between the lid and the edge of the opening. 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 absorbed, so the gap between the lid and the edge of the opening becomes as small as possible.Moreover, this leakage radio wave absorber has the ability to absorb radio waves except for the part where hard ferrite is mixed. Since the mixed part is formed to be buried inside the soft ferrite mixed part, it is always the soft ferrite mixed part 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 leakage of radio waves is effectively prevented.

〔Example〕

The details of the present invention will be explained based on further illustrated embodiments. Regarding the leakage radio wave absorber according to the present invention as shown in FIG. It is provided on one side to absorb leakage radio waves from inside the container body 1. That is, as shown in FIG. 1, numeral 4 in the figure is an annular sheet member for absorbing radio waves, and this member has approximately the same shape as the opening rim 2 of the microwave oven container body as shown in the figure, and is made of soft ferrite such as nickel zinc ferrite, Manganese zinc ferrite, magnesium zinc ferrite, etc. are dispersed and mixed into a synthetic resin such as polypropylene, polyamide, polyphenylene sulfide, vinyl chloride, etc., and this is molded into the above-mentioned annular sheet member 4 to be used as a radio wave absorbing material. At the same time as the soft ferrite-containing part, the annular sheet member 4 is formed.
For example, at the center of the annular sheet member 4 in the width direction and in the longitudinal direction of each side of the annular sheet member 4, there is a magnet for magnetically attaching the container body opening edge 2 and the inner surface of the lid 3 to each other. The permanent magnet 5 is formed in a buried state with a soft ferrite mixed portion as a radio wave absorbing material remaining on the surface. The permanent magnet 5 is made by mixing barium ferrite or strontium ferrite into the same synthetic resin as the binder of the soft ferrite mixed part, molding this part integrally with the soft ferrite mixed part by means such as biaxial molding, and magnetizing the part. It is formed by In FIGS. 1 and 2, the rectangular portion indicated by solid lines in the center of each side of the annular sheet member 4 is the position where the permanent magnet 5 is arranged, and the cross-sectional structure of this portion is shown in FIG. 3. The thickness of the annular sheet member is set to be extremely small compared to the width. This leakage radio wave absorber has a soft ferrite mixed part that has radio wave absorbing ability except for the partially provided hard ferrite mixed part, and the hard ferrite mixed part is buried in the soft ferrite mixed part. , a soft ferrite-containing part is located on its surface. The hard ferrite part has its magnetization direction set in the thickness direction of the hard ferrite part, like a normal attracting magnet, so that it can absorb the facing lid or the edge of the opening.

Such a leakage radio wave absorber is disposed on at least one of the inner surface of the lid 3 that opens and closes by contacting the opening rim 2 of the microwave oven container body 1, or the opening rim 2 of the main body, and is designed to absorb energy from the gap between the lid and the opening rim. It is possible to absorb and attenuate radio waves that are about to leak, thereby preventing radio waves from leaking from the relevant part.

[Effect of idea]

This leakage radio wave absorber forms a hard ferrite mixed part as a permanent magnet in a part of the annular sheet-shaped soft ferrite mixed part as a radio wave absorbing material,
All parts other than the hard ferrite mixed part are made of soft ferrite mixed parts having radio wave absorption ability, and the hard ferrite mixed part is embedded in the soft ferrite mixed part such that the soft ferrite mixed part remains on the surface. Therefore, it is possible to adsorb the lid to the rim of the opening and close the lid and the rim of the opening in close contact with the soft ferrite-containing part having radio wave absorption ability interposed therebetween. Radio waves that are about to leak from between the edges can be reliably caught and attenuated by the soft ferrite mixed portion. 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 suctioned, so the gap between the lid and the rim of the opening is made as small as possible. Moreover, all parts other than the partially provided hard ferrite mixed part are soft ferrite mixed parts, and since there is always a soft ferrite mixed part on the front side of the hard ferrite mixed part, there is no possibility of contact with the lid or opening edge. is always 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. In addition, since the hard ferrite mixed part, which is a permanent magnet, is only partially provided, the magnetic field generated by the permanent magnet does not magnetically saturate the soft ferrite mixed part, and there is also a hard ferrite mixed part. Since the hard ferrite mixed part is magnetized so that the facing lid or opening edge can be attracted, the magnetic flux emitted from the hard ferrite mixed part mainly goes in the thickness direction of the hard ferrite mixed part. That will happen. For this reason, the magnetic flux emitted from the hard ferrite mixed part hardly crosses the soft ferrite mixed part located on the widthwise side of the hard ferrite mixed part, so the soft ferrite mixed part does not become magnetically saturated. does not impair its radio wave absorption ability. In addition, since the magnetic flux passes through the soft ferrite-containing part that covers the surface of the hard ferrite-containing part, the radio wave absorbing ability is slightly reduced, but it is possible to impart some radio wave absorbing ability to that part as well. By assisting the radio wave absorption by the soft ferrite mixed part located adjacent to the hard ferrite mixed part, leakage of radio waves can be more reliably prevented.

Furthermore, since this leakage radio wave absorber is in the form of a sheet and has a small thickness, it passes through the width direction of the sheet, that is, the gap formed by the lid and the edge of the opening, from the container side entrance toward the outside of the container. Although it has excellent radio wave attenuation ability, its 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. or,
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 thermal expansion coefficients of the soft ferrite mixed part and the hard ferrite mixed part are almost the same, cracks etc. can occur between the soft ferrite mixed part and the hard ferrite mixed part due to the difference in thermal expansion. It doesn't even come in.

[Brief explanation of the drawing]

FIG. 1 is an explanatory perspective view of a leakage wave absorber according to the present invention, FIG. 2 is an explanatory perspective view of a microwave oven using the same, and FIG. 3 is a cross-sectional explanatory view of the same embodiment. 1... Container body, 2... Opening rim, 3... Lid,
4... Annular sheet member for absorbing radio waves, 5... Magnet.

Claims (1)

[Scope of utility model registration request] An annular sheet whose overall shape is approximately the same as the opening rim of the microwave oven, and which is disposed on at least one of the inner surface of the lid or the rim of the main body which opens and closes by contacting the rim of the opening in the container body of the microwave oven; The sheet has a main body containing a soft ferrite mixture, which is a radio wave absorbing material made by dispersing and mixing soft ferrite in a synthetic resin, and a part of the soft ferrite mixture remains on the surface side. In this state, a hard ferrite mixed portion in which hard ferrite is dispersed and mixed in a synthetic resin is formed in an embedded state, and the soft ferrite mixed portion and hard ferrite mixed portion are integrally molded, and the hard ferrite mixed portion is magnetized. A leakage radio wave absorber made of a permanent magnet.