JPH04303897A - Sound insulating material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is lightweight and has high sound insulation performance.
The present invention also relates to a sound insulation material that is easy to install.

0002

BACKGROUND OF THE INVENTION In recent years, with improvements in living standards, troubles caused by external noises such as sounds from neighboring houses or rooms and traffic noises have been increasing. Furthermore, with the increase in the number of high-rise buildings, there is a strong demand for reducing the weight of buildings. For this reason, there is a strong demand for sound insulation materials that are lightweight and have high sound insulation performance.

[0003] Conventionally, regarding sound insulation by a single wall, the mass law that states that the sound transmission loss (D) is proportional to the areal density of the wall surface is well known. Also, multiple sound insulation walls are used to overcome the mass law problem with single walls. For example, the transmission loss of two 21 mm thick plywood sheets bonded together is approximately 5 db per octave, as shown in Figure 5.
On the other hand, when the above plywood is installed to form a completely independent double wall, it rises at a rate of about 10 db per octave, as shown in the figure. Also, the above plywood is 3c
When installed with a gap of m, the sound insulation characteristics shown in the figure can be obtained.

It is known that in a sandwich panel in which different materials are sandwiched between double walls as a core material, the sound insulation performance differs depending on the core material. For example, in a structure in which sound-absorbing material is sandwiched between plywood or plasterboard, as is often done, the transmission loss will be large at high frequencies, but in the middle and low frequencies, the core material will act as stiffness, just like a hollow double wall. only works. On the other hand, if a highly rigid honeycomb core is used as the core material, the front and back sides can be considered to vibrate as one at low frequencies, so it can be considered as a single wall. for example(
Figure 6) shows the relationship between transmission loss and frequency for honeycomb panels of different thicknesses (Acoustic Engineering Course 3, Architectural Acoustics, Corona Publishing, p. 101). As is clear from the figure, since the panel has high rigidity, it exhibits higher transmission loss than the mass law at low frequencies.

[0005]

[Problems to be Solved by the Invention] However, the above sound insulation materials have the following problems. In order to realize a single wall with a large transmission loss, there was a problem in that the weight of the wall would be large. In addition, in order to ensure the independence of the walls with double walls, it is necessary to leave at least 20 to 30 cm between the walls, which poses the problem of reducing the living space. Moreover, in reality, the front and rear walls were connected using studs, making it impossible to create completely independent walls. Furthermore, when the distance between walls is small, sound insulation loss occurs due to resonance transmission at the frequency shown by (Equation 1).

[0006]

[Math 1]

For this reason, the wall distance l shown in (Equation 1)
When is made small, the resonant transmission frequency fc becomes high, causing a sound insulation defect in the important mid-high range. For example, in the previous example, 1
Sound insulation defects occur around 40Hz.

[0008] In view of these problems, the present invention provides a sound insulating wall that is lightweight, has excellent workability, and has high sound insulating performance.

[0009]

[Means for Solving the Problems] In order to solve the above problems, the sound insulating wall of the present invention includes a core material, a surface material provided on both sides of the core material via a viscoelastic material, and a space filled with the core material. It has a sound absorbing material.

0010

[Operation] According to the structure of the present invention, since the front and back sides move as one at low frequencies, it exhibits sound insulation characteristics higher than the mass law, similar to honeycomb panels. Furthermore, at high frequencies, because of the viscoelastic body between the core material and the surface material, the front and back surfaces come to work as independent walls. Therefore, it exhibits the sound insulation characteristics of a double wall, increasing at a rate of 10 dB per octave. Moreover, the sound-absorbing material filled in the space of the core material further improves the high-frequency sound insulation properties.

[0011]

[Embodiment] An embodiment of the present invention will be described below with reference to FIG. 1. 1 is 90cm long, 90cm wide, and 10cm thick.
A wall surface is constructed by using a sound insulating panel of 1.5 cm in diameter and fixing it to a frame (not shown) by passing bolts through holes 2 provided at the four corners. The surface material 3 of the panel is plywood with a thickness of 20 cm and an areal density of 13 kg/m2. The core material part consists of an outer peripheral frame 4 and reinforcing bars 5, and a vibration-proof rubber sheet 6 with a thickness of 3 mm is pasted on the surface thereof. Further, the space of the core material is filled with glass wool 7 having a density of 48 kg/m2. The total weight is 25 kg and the equivalent surface density is 31 kg/
It is m2. When we measured the sound insulation properties of this panel, we found that
(Figure 2). fc calculated from (Equation 1)
is 135Hz, but the measurement results do not show any significant sound insulation deficit. In addition, at low frequencies, the front and back sides vibrate as one, so it acts as a single wall, and like honeycomb panels, it achieves higher sound insulation performance than the mass law.

Next, regarding the second embodiment of the present invention (FIG. 3
). In FIG. 3, 31 is an aluminum honeycomb core, 32 is a viscoelastic sheet, 33 is a surface material, and 34 is a sound absorbing material, all of which are the same as those used in the first embodiment. In this example, since aluminum honeycomb was used as the core material, the rigidity was higher and the low-frequency sound insulation characteristics were further improved. Note that a frame may be constructed on the outer periphery in order to ensure sound insulation between adjacent panels and to provide holes for mounting.

Next, regarding the third embodiment of the present invention (FIG. 4
). Reference numeral 31 designates the aluminum honeycomb core used in the second embodiment, in which an intermediate surface material is provided between two layers of the core, and surface materials are provided on both sides. Also, similar to the second embodiment, a viscoelastic sheet 32 is provided between the core material, the intermediate surface material, and the surface material, and a sound absorbing material is provided in the space between the core materials.

[0014] Conventionally, multi-wall sound insulation structures are expensive and time-consuming to construct, and low resonance transmission frequencies occur at a plurality of frequencies, resulting in sound insulation defects over a wide range of frequencies. Therefore, extremely high sound insulation performance is required,
It was only used when sufficient space between walls could be secured. However, in this example, the triple wall structure is integrally formed, so the work on site is the same as when constructing a single panel. Moreover, as explained earlier, since it acts as a single wall in the low range, it is possible to achieve good sound insulation characteristics without any sound insulation loss. Furthermore, in the middle and high ranges, it has triple wall characteristics, and the transmission loss increases by 15 dB per octave, making it possible to achieve extremely high sound insulation performance.

In the above embodiments, the thickness of the core material and the surface material were kept constant, but by varying the thickness of each core material and surface material, it is possible to prevent the deterioration of sound insulation properties in the mid-high range due to the coincidence effect. Of course it can be prevented.

[0016]

[Effects of the Invention] As explained above, the present invention includes a core material, a surface material provided on both sides of the core material via a viscoelastic material, and a sound absorbing material filled in the space of the core material. By operating the material as a single wall in the low frequency range and as a multilayer wall in the middle and high frequencies, it is possible to provide a lightweight sound insulation material that has excellent sound insulation performance over a wide frequency range and is easy to install.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the configuration of a first embodiment of the present invention.

[Figure 2] Frequency characteristic diagram of transmission loss of conventional sound insulation material and sound insulation material of the present invention

FIG. 3 is a sectional view showing the configuration of a second embodiment of the present invention.

FIG. 4 is a sectional view showing the configuration of a third embodiment of the present invention.

[Figure 5]
Frequency characteristic diagram of transmission loss of conventional sound insulation materials

[Figure 6] Frequency characteristic diagram of transmission loss of conventional honeycomb panel

[Explanation of symbols]

1. Sound insulation panel 2 Hole 3 Surface material 4 Outer frame 5 Reinforcement material 6 Anti-vibration rubber sheet 7 Glass wool 31 Aluminum honeycomb core 32 Viscoelastic sheet 33 Surface material 34 Sound absorbing material

Claims (8)

[Claims] 1. A core material having a space inside, a surface material provided on both sides of the core material via a viscoelastic material, and a sound absorbing material filled in the space of the core material. Sound insulation material. [Claim 2] A plurality of core members having spaces inside;
an intermediate surface material provided between the core materials, a surface material provided on the surface of the outermost core material, and a viscoelastic body provided between the core material and the intermediate surface material or the surface material; A sound insulating material comprising a sound absorbing material filled in the space of the core material. 3. The sound insulating material according to claim 1 or 2, wherein the core material comprises an outer peripheral frame and reinforcing members arranged around the outer peripheral frame in a substantially lattice shape. 4. The sound insulation material according to claim 1, wherein the core material is a honeycomb structure. 5. The sound insulation material according to claim 1, wherein the plurality of core materials have at least two different thicknesses. 6. The sound insulation material according to claim 1, wherein the plurality of surface materials and the intermediate surface materials have at least two different surface densities. [Claim 7] A highly rigid core material is used so that the surface materials on both sides vibrate together at the resonant transmission frequency determined by the areal density of the surface material or the intermediate surface material and the stiffness of the space of the core material. Characteristic claims 1 to 6
Sound insulation material as described. 8. The core material, the viscoelastic material, the surface material, and the sound absorbing material are integrally formed and processed for attachment to the frame. Sound insulation material.