Patent Translate Powered by EPO and Google Notice This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate, complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or financial decisions, should not be based on machine-translation output. DESCRIPTION JPS52149112 Patent application title: Back Cavity for Medium to High Tone Loudspeaker and Method of Manufacturing the Same 2, the scope of claims 3. Detailed Description of the Invention The present invention relates to a lock cavity of a middle to high-tone speaker. In order to prevent the medium and high-pitched speaker from being adversely affected by the sound emitted from the back of the low-pitched speaker close to the middle-to-high-pitched speaker, (in many cases, ivy cavities are provided) It is normal. Recently, it has become popular to use foam concrete having open cell pores, foam of metal such as aluminum or foam plastic as a sound absorbing material of the back cavity. An object of the present invention is to provide a back cavity which has a sound absorbing material made of foam having open cell pores and which is simple in structure and easy to manufacture. Another object of the present invention is to provide a method of manufacturing such a back cavity. FIG. 1 shows a cross section of the back cavity of a high to high frequency speaker according to the present invention. (1) is a block of foam having open cell holes, and the foam block is made of concrete, aluminum, plastic or the like. At one end of the foam (1), a hooked annular body (2) is provided as a speaker supporting means. The end face of the foam on the side to which the annular body (2) is attached is provided with a mounting hole (3) for attaching the speaker directly or through the baffle plate on the annular body (2) In order to improve the sound absorption characteristics, it is processed to open the bubble hole. The exposed side and bottom of the foam block (1) are covered by a gas tight membrane (4). The hermetic membrane (4) is made of a suitable synthetic resin or the like. The back cavity having the above-described structure has sufficient sound absorption characteristics due to the presence of the airtight film (4), but is easy to manufacture because of its simple structure. This is a case where the storage 02-05-2019 1 case of the sound absorbing material used in the conventional one is omitted by utilizing the fact that the foam block (1) has a strength of 9. Next, a preferred method 4c) of manufacturing the bath cavitation as described above with reference to FIGS. Light up. In manufacturing the back cavity of FIG. 1, first, a columnar foam block (1 ') as shown in FIG. 2 is formed using a cylindrical mold. Then, a column block (one is cut into a desired length in a plane substantially perpendicular to the axial direction thereof to make a small profile as shown in FIG. 3). Next, in order to provide an airtight film on the exposed surface of the foam block (1), the exposed surface is dipped in a resin solution (5) as shown in FIG. 5, and then pulled up and dried. You may apply ¦ coat with a brush etc., without being immersed in this braided resin solution. As a resin solution, unlike a vinyl acetate emulsion or the method described above, a bag-like film (6) made of a heat-shrinkable resin is covered as shown in FIG. 6 so as to cover the exposed surface of the foam block (1). After being provided, the bag-like membrane (6) can be contracted by heating to obtain the airtight membrane (4). In addition, it is desirable that the thickness of the airtight film be about 10 μ or more, which is a thickness that does not cause pinholes. By the above-described manufacturing method, the desired back cavity can be obtained by a small number of steps without requiring complicated machining. 4. Brief Description of the Drawings FIG. 1 is a sectional view showing a back cavity according to the present invention, and FIGS. 2 to 6 are views showing steps of a manufacturing method for obtaining the back cavity of FIG. DESCRIPTION OF MAIN CODES 1 ··· · · · · · · · · · · · · · · · · · · · · · · Annulus 3 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · airtight film 5 ........ resin bath 6 ......... heat-shrinkable resin applicant Pioneer Corporation EndPage: 2 02-05-2019 2
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