JPS6154899B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sound insulating panel characterized in that a large number of horn-shaped small spaces are formed on the inner or outer surface, and is particularly effective in the frequency range below the horn cutoff frequency. Has sound insulation properties,
This provides a sound insulating panel suitable for architectural panels, etc.

A horn has a cutoff frequency _c determined by its size and shape, and has the characteristic that sound does not propagate at frequencies lower than this cutoff frequency. Figure 4 shows the real part of the specific acoustic impedance of various horns showing this relationship. FIG. In Figure 4, S _p is the cross-sectional area of the throat of the horn, S is the cross-sectional area at distance x from the throat, m is the expansion coefficient, the horizontal axis is 2k/m (k = ω/c), and the vertical axis is is the degree of passage T that indicates the rate at which sound energy propagates through the cross section of the horn, curve A in the figure is S = S _p mx, that is, in the case of a conical horn, B is S = S _p mx ² , and C is S = S _p mx ⁹ , then D is S = S _p e ^mx
That is, it shows the respective characteristics in the case of an exponential horn. For example, in a conical horn, the degree T of sound energy passing through the cross section of the horn is 15% at frequencies lower than 500Hz.
To find the horn shape as shown below, use the fourth
From the figure, 2k/m≦50 where k=ω/c=2π/c: frequency (Hz) c: sound speed (m/sec), so 2×2π/m×340≦50 /m≦50×340 /4π=1352.8 =500, so m≦0.37, and the expansion coefficient m is determined. Therefore, by determining S _p in addition, the shape of the horn can be determined from the cutoff frequency _c and the degree of passage T.

The present invention utilizes such characteristics of the horn, and the embodiment shown in the drawings will be described below.
FIG. 1 shows a part of the cross section of the first embodiment, in which several types of conical horns 3, 3... having different shapes and dimensions are placed on one side of a substrate 2, with throat portions 3a facing outward, and openings 3b. The sound insulating panel 1 is constructed by bonding the sides. The conical horns 3, 3... are distributed randomly or in an array so as to be in close contact with each other on the entire surface of one side of the substrate 2, so that even if a sound wave with a frequency below _c comes to the throat 3a of the horn 3, the opening 3b side, that is, the surface of the substrate 2, and the transmission loss increases in the frequency range below _c . Also
Even in the frequency range above _c , as shown in Fig. 4, the rise of curve A is gradual and the degree of transmission T does not increase immediately, so even above _c , the transmission loss increases and excellent sound insulation properties can be obtained. Furthermore, since the conical horns 3, 3, . . . are not the same in shape and size and have different cut-off frequencies, the overall sound insulation characteristics can be adjusted by combining these horns.

Figure 2 shows a large number of conical horn-shaped holes 4, 4...
A plurality of sheets 5, 5... having holes therein are stacked and sandwiched between the substrates 2, 2, and each sheet 5 has a conical horn-shaped hole 4...
The cutoff frequency is changed by changing the shape and dimensions of the
Therefore, appropriate sound insulation characteristics can be obtained as a whole, and since the sheet 5 is made of multiple layers, a sound insulation panel having an excellent sound insulation effect can be obtained.

FIG. 3a shows still another embodiment, in which a large number of conical spiral cores 6 as shown in FIG. 3b are bonded between two substrates 2. The conical spiral core 6 is compressed and placed between the substrates 2, and a large number of small spaces are formed in which conical horns of different sizes are stacked one upon another. In this embodiment, there is a large space between the substrates 2, 2, and since the core 6 itself can be made of a material such as cardboard, the sound insulating panel 1 can be made lightweight as a whole.

In each of the above embodiments, a small space shaped like a conical horn is formed, but this is because it is easy to calculate and manufacture, and the shape of the horn is shown in curves B, C, and D in Fig. It is also possible to choose a shape with a curved surface of quadratic or higher order as shown in the example, and in addition to a cone or a truncated cone, it can also be a pyramid or a truncated pyramid, and only one type or several types of these horns can be used. They are used by appropriately mixing them.

As mentioned above, since the sound insulation panel of the present invention has a large number of horn-shaped small spaces, it is possible to use the cutoff frequency of the horn to create a panel that is relatively lightweight but has a large transmission loss. In addition, many horn-shaped small spaces with different shapes and dimensions and different cut-off frequencies are formed, so the overall sound insulation characteristics can be adjusted by combining these horns with different cut-off frequencies. be. In this way, by appropriately selecting the shape and dimensions of the horn, it is possible to adjust the cutoff frequency and obtain excellent sound insulation properties over a wide frequency range, making it a suitable sound insulation material for architectural panels, especially wall materials. It has the advantage that panels can be easily obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of one embodiment of the present invention, Fig. 2 is a partially cutaway perspective view of another embodiment, Fig. 3a is a sectional view of yet another embodiment, and Fig. 3b is the same embodiment. A perspective view of the core used in the example, and FIG. 4 are characteristic diagrams of various horns. 1 is a sound insulation panel, 2 is a substrate, 3 is a conical horn, 4 is a hole, 5 is a sheet, and 6 is a conical spiral core.

Claims (1)

[Claims] 1. A sound insulating panel formed by forming a large number of horn-shaped small spaces of different shapes and dimensions and different cutoff frequencies. 2. Claim 1 comprising several types of horns with different cut-off frequencies distributed on one side of the substrate.
Sound insulation panels as described in section. 3. A plurality of sheets having a large number of horn-shaped holes are stacked and interposed between two substrates, and the horn shape of each sheet is changed so that the cutoff frequency of each sheet is set to a different value. The sound insulation panel described in item 1. 4. The sound insulation panel according to claim 1, wherein a large number of conical horns are formed by bonding a large number of conical spiral cores between two substrates.