JPH02253297A - Sound absorbing device - Google Patents

Abstract

PURPOSE:To provide the device having broad sound absorbing characteristics over the entire register by adopting a honeycomb core structure integrated with an oscillation diaphragm by mounting of skin plates on both sides of a honeycomb core material, removing one of the surfaces forming one core of the honeycomb core material and dividing the spaces of the cores to plural pieces in random positions. CONSTITUTION:The oscillation diaphragm 4 is integrated by adhering aluminum skins 4a, 4b having a uniform surface density to both surfaces of the hexagonal columnar honeycomb core material 4c made of paper having the many cores 4d. Plural pieces of the side faces of the hexagonal columns of the respective cores 4d having the same shape to constitute the honeycomb core material 4c are removed to form the spaces connected with the adjacent hexagonal columns to each other. Polygonal columns, exclusive of the hexagonal columns, are otherwise constituted by adding partition plates to constitute the fresh side faces into the connected spaces. The individual cores 4d constituting the honeycomb core material 4c have the plural sectional areas of different shapes in such a manner. As a result, the resonance frequencies of the aluminum skin material 4a are dispersed and the sound absorbing characteristics in a high register are flattened and the sound absorbing characteristics in the entire register are broadened.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a sound absorbing device.

[Prior Art] Conventionally, an air chamber 6 has been formed in a box 1 as shown in FIGS. 2 to 4 as a sound absorbing device installed in a listening room, musical instrument practice room, etc. with the aim of improving acoustic characteristics. In the opening 3 of the baffle plate 2 installed so that
A honeycomb core material 4 is inserted through an edge 5 made of a flexible film.
C and aluminum skin materials 4a, 4 with -like areal density on both sides.
It has been proposed that a diaphragm 4 made by bonding a diaphragm 4 is provided.

Here, in the conventionally used honeycomb core material 4c, all of the individual cores have the same size, and as a result, on the surface of the aluminum skin material 4a, the individual cores of the honeycomb core material 4C have the same size. The area divided by is constant.

The sound absorption characteristics of the sound absorption device configured as described above are shown in FIG. 5, where the horizontal axis represents frequency and the vertical axis represents sound absorption coefficient.

As is clear from Figure 5, the conventional sound absorbing device has a low frequency range (
200Hz), midrange (500Hz), treble range (3,1
It has sound absorption properties with a peak at 5kHz).

Among these, the sound absorption characteristics in the high frequency range, which is particularly problematic, are mainly contributed by the sound absorption characteristics of the diaphragm 4 itself. That is,
In response to the sound generated in the air chamber, the aluminum skin material 4a on the outside air side causes resonance, absorbs the sound energy, and exhibits a sound absorption effect.

Here, the sound absorption characteristics of the conventional diaphragm 4 alone are shown in FIG. 6. From this FIG. 6 and FIG.
It can be seen that the sound absorption coefficient decreases at 1.6kHz,
This is because the sound absorption characteristics of the diaphragm 4 deteriorate in this frequency band.

However, it is desirable that sound absorbing devices installed in listening rooms, musical instrument practice rooms, etc. have broad sound absorbing characteristics over the entire band, and conventional sound absorbing devices have had problems with this requirement.

[Problems to be Solved by the Invention] The sound absorbing device of the present invention has been made in view of the above problems, and its purpose is to provide a sound absorbing device having broad sound absorbing characteristics over the entire sound range. There is a particular thing.

[Means for Solving the Problems] In order to solve the above problems, the sound absorbing device of the present invention includes a box forming an air chamber to which a baffle plate having an opening is attached, and a box that closes the opening of the baffle plate. In a sound absorption device consisting of a diaphragm arranged in the shape of a diaphragm and an edge that is connected to a baffle plate and supports the diaphragm so as to vibrate freely with respect to the baffle plate, the diaphragm is attached to a honeycomb core material with skin plates on both sides. It is possible to create an integrated honeycomb core structure by removing one of the surfaces forming one core of the honeycomb core material and making the space between adjacent cores a continuous space, or by creating a new vertical partition in the core. The sound absorbing device is characterized in that the space of the core is divided into multiple parts at random positions within the diaphragm, so that the area of the membrane of the skin material divided by the core exists for many milliseconds. In this device, the honeycomb core material is made of paper, synthetic resin, etc. in addition to aluminum, and the same applies to the skin material.

The shape of the core constituting the honeycomb core material is usually a hexagonal column, but in addition to the hexagonal column, it may also be a square column or a non-uniform core.

Examples of the material for the edges include rubber-like elastic bodies and rigid thin metal plates.

[Example] Embodiments of the invention are disclosed in the drawings.

Note that the configuration other than the diaphragm 4 is the same as the conventional one, so only the diaphragm 4 will be described.

FIG. 1 is an exploded perspective view of a diaphragm of a sound absorbing device according to an embodiment of the present invention.

As shown in FIG. 1, the diaphragm 4 of the present invention has a large number of cores 4.
Aluminum skins 4a and 4b with uniform surface density are adhered to both sides of a hexagonal columnar honeycomb core material 4C made of paper having a diameter d, and are integrated.

Here, a plurality of side surfaces of the hexagonal columns of each core 4d having the same shape constituting the honeycomb core material 4C are removed to form a space in which adjacent hexagonal columns are connected,
Alternatively, by adding a partition plate that becomes a new side surface in the connected space, and forming a polygonal column other than a hexagonal column, the individual cores 4d constituting the honeycomb core material 4C can be It has a cross-sectional area of the shape.

The high-frequency sound absorption effect of the diaphragm with this structure is that the aluminum skin material 4 on the outside air side absorbs the sound generated in the air chamber.
a resonates, causing membrane vibration and absorbing sound energy, producing a sound absorption effect.The resonant frequency of membrane resonance usually varies depending on the area, shape, density, and tension of the membrane. Become something.

In this embodiment, an aluminum skin material 4a is applied to a honeycomb core material 4c consisting of a large number of cores 4d having a plurality of different shapes and cross sections. The aluminum skin material 4a is divided into different shapes and areas, and the aluminum skin material 4a is a film having a plurality of different resonance frequencies.

As a result, the resonance frequency of the aluminum skin material 4a is dispersed, the sound absorption characteristics in the high frequency range become flat, and the sound absorption characteristics in the entire sound range become broad.

[Effects of the Invention] As shown above, the sound absorbing device of the present invention includes a box forming an air chamber to which a baffle plate having an opening is attached;
A sound absorbing device comprising a diaphragm arranged to close an opening of a baffle plate, and an edge that spans the baffle plate and supports the diaphragm so as to vibrate freely with respect to the baffle plate,
The diaphragm is made into an integrated honeycomb core structure by attaching skin plates to both sides of the honeycomb core material, and one of the surfaces forming one core of the honeycomb core material is removed to make the space between adjacent cores a continuous space. Alternatively, by inserting new partitions in the core in the vertical direction and dividing the core space into multiple pieces at random positions within the diaphragm, the area of the membrane of the skin material divided by the core can be Since the sound absorbing device is characterized in that there are many types of sound absorbing devices, it is possible to provide a sound absorbing device having broad sound absorbing characteristics over the entire sound range.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of a diaphragm of a sound absorbing device according to an embodiment of the present invention, FIG. 2 is a perspective view of a conventional sound absorbing device, and FIG.
The figure is a sectional view of the same as above, Figure 4 is an exploded perspective view of the same as the above diaphragm, Figure 5 is a graph showing the sound absorption characteristics of the conventional sound absorbing device, and Figure 6 is the sound absorption of only the same as the above diaphragm. It is a graph showing characteristics. l...Box, 2...Baffle plate, 3--Sekiguchi section, 4...-1lseJJFx, 4 a, 4 b
-Skin material, 4C/\Nicum core material, 4d...-Core, 5-Edge, 6--Air chamber.

Claims (1)

[Claims] (1) A box forming an air chamber equipped with a baffle plate having an opening, a diaphragm arranged to close the opening of the baffle plate, and a diaphragm that hangs over the baffle plate and vibrates the diaphragm against the baffle plate. In a sound absorbing device consisting of a freely supporting edge, the diaphragm has a honeycomb core structure in which skin plates are attached to both sides of a honeycomb core material, and one of the surfaces forming one core of the honeycomb core material is By removing and making the space between adjacent cores a continuous space, or by inserting new partitions in the core in the vertical direction and dividing the core space into multiple pieces at random positions within the diaphragm. A sound absorbing device characterized in that the skin material membrane divided by the core has many different areas.