JPS5836799B2 - Soundproof structure for solid-state sound generating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sound insulating structure for equipment that generates solid sound caused by cutting, deformation, friction, impact, etc. of solid objects.

Conventionally, the following methods have been adopted as soundproofing measures for equipment that generates solid-state sound.

(1) Install a soundproof wall separately from solid-state sound generating equipment.

(2) Attach sound-absorbing material to the surface of solid-state sound generating equipment.

(3) Adding a damping material to attenuate energy through a damping effect.

In addition to dividing and attenuating the energy of the vibration system, the conventional method described above does not provide a double wall, which is effective for soundproofing, directly on the surface of the solid-state sound generating equipment, so it is difficult to avoid coincidences.
) There is a limit to the transmission loss value because a drop in transmission loss due to the effect cannot be avoided.

According to the experimental results conducted by the present inventor showing the relationship between the acoustic system and the vibration system, even if a vibration isolation mechanism is installed in a solid-state sound generating device to remove 30% of the vibration acceleration (dB) of the vibration system, the acoustic system However, only a 2.5 dB improvement in transmission loss could be obtained.

Therefore, after attenuating the vibrations of the equipment using anti-vibration rubber, damping materials, etc., a soundproof plate that can attenuate the vibration system energy corresponding to the acoustic system and prevent transmission of acoustic system energy is placed on the outside of the equipment that generates solid sound. As a result of experiments, the present inventor discovered that a gap should be provided.

In this invention, the free space board refers to a soundproof board that forms a free air layer between it and the outer surface of the solid-state sound generating device.

Next, this invention will be specifically described.

In this invention, a free space plate is connected to the outer surface of a solid-state sound generating device by a connecting joint having a connecting structure that divides and attenuates forced vibrations from the device.

When using a single free space plate, a metal plate such as iron, aluminum, or lead is used, and the thickness of the plate is 1 to 4 ml.
are used practically.

When using sand inch panels as free space boards, the above metal plates, non-metal plates (e.g. gypsum slate, gypsum board, synthetic resin plates) should be attached together, or both metal plates and non-metal plates should be attached with a polymeric viscous adhesive. A combined sanderch panel is used.

Examples of the polymeric viscous adhesive include rubber-based adhesives, epoxy-based adhesives, vinyl-based adhesives, copolymers thereof, and compositions based on these adhesives (for example, asalto emulsion mixed with vinyl acetate ethylene copolymer).

The thickness of the polymer viscous adhesive layer is set to 0.00 mm to prevent both plates to be adhered from destroying the adhesive layer and becoming directly connected. 2 mm or more is desirable, and about 0.2 to 2.0 mm is practical.

This polymer viscous adhesive layer enhances vibration damping through energy conversion due to strain effects and contributes to the absorption of acoustic system energy.

By providing a free space plate on the outer surface of a device that generates solid sound, opposing damped resonance occurs within the free air layer formed between the outer surface of the device and the free space plate, and when a sanderch panel is used as the free space board, multilayer opposing damped resonance occurs. As a result, excellent transmission loss values can be obtained.

Any of the above-mentioned free space plates connected by the connecting joints described later are flat or curved, and in particular, by making them curved (concave or convex), the acoustic system energy incident toward the curved surface is reflected by the curved surface. This is preferable because the repetition of diffusion, interference, and attenuation improves counter-damped resonance even more than in a flat free-space plate, resulting in superior transmission loss values.

Free-space plates having flat or curved surfaces can be used in combination depending on the shape of the solid-state sound generating device.

The free air layer formed by the free space plate has a longitudinal force perpendicular to the crossbeam or equipment surface to bind it to a certain resistance characteristic, including the air density and the sound absorbing material filled in the free air layer. A free air layer divided into several sections is formed by connecting joints in both directions.

The thickness of the free air layer is appropriately selected according to the maximum average value determined by the fundamental resonance frequency, and is 40 to 150.
Selected within the range of mm.

As mentioned above, acoustic waves are incident on a partitioned free air layer,
Repeated reflection and transmission.

During this time, the external surface of the solid-state sound generating device and the free space plate receive opposing damping resonance or multi-layer opposing damping resonance as described above, and further receive resistance damping and rectifying wave effects due to the sound absorbing material, resulting in excellent transmission. It shows loss and sound absorption.

Note that the soundproofing properties can be particularly improved in the low frequency region in accordance with the soundproofing requirements of solid-state sound generating equipment.

FIG. 1 shows an example of the results of an experiment conducted to confirm the effect of stretching a free space plate, and shows the transmission loss value (decibel dB) versus frequency (Hertz Hz).

The solid line I in the figure indicates the wall thickness of the solid-state sound generating device. 5 m.
(iron plate), the dashed line indicates the plate thickness 1. The one with a 0 mm iron plate (single free space plate), the dot-dashed line in ■ is 1. A sandwich panel in which 0 mm iron plates were laminated with a 0.2 mm rubber adhesive layer was provided as a free space plate with a gap of 50 mm.

As seen in the figure, the transmission loss value can be increased by providing a free space plate on the outer surface of the device where solid sound is generated.

In particular, when a Sanderch free space board is installed, the effect is 10 d in the frequency range effective for dogs (500 Hz or more).
This shows an improvement in transmission loss over B.

Figure 2 shows the results of an experiment to confirm the effect of filling a sound absorbing material (for example, artificial mineral fiber) into the free air layer formed by the free space plates. It is provided with a polymer viscous adhesive layer (approximately 2 mm thick) interposed therebetween so as not to be subjected to forced vibration.

The solid line I' in the figure is a single free space plate with a thickness of 1 mm of aluminum installed on the wall of the solid-state sound generator with a free air layer of 50 mm, and the solid line ``■'' is inside the free air layer of I' above. A glass wool bundle with a thickness of 12 mm was inserted.

The broken line indicates the case where a glass wool bundle with a thickness of 12 mm is inserted into the free air layer formed under the same conditions as described in I' except that the single free space plate is an iron plate with a thickness of 1 ml. It is shown by the broken line W'.

As shown in the figure, it is confirmed that when the free air layer is filled with a sound absorbing material, the transmission loss approximately follows the mass law of the free space plate in the frequency range of 500 Hz or less.

As described above, the transmission loss value can be further improved by filling the free air layer with artificial mineral fibers having a large mass such as glass wool, rock wool, or slag wool or inserting them as a bundle as a sound absorbing material.

According to another experiment, the mass of sound absorbing material in the free air layer is 3
．． 3kg/7? Frequency 500Hz due to mass difference of Z2
The transmission loss value was improved by 2 dB or more below.

As mentioned above, the decision as to whether or not to incorporate a sound absorbing material within the free air layer is determined as appropriate depending on the required soundproofing properties.

The following two methods are used to connect the free space plate to the outer surface of the solid-state sound generating device.

One is to install connecting arms with the tops formed into fitting ridges outward at appropriate intervals on the wall of the solid-state sound generating device, and bend both edges of a free space plate made of a metal plate with a curved surface. This method uses the repulsive force of the curved surface of the free space plate to interpose a polymer adhesive layer between the connection arms and the connection skirt of the free space plate to connect them by fitting. It is.

This connection joint force type can form any curved surface relative to the shape of the solid sound generating device, and the vibration system,
It is possible to prevent the acoustic system energy from leaking, and furthermore, as mentioned above, since the incident acoustic system energy is reflected by the curved surface, the transmission loss can be improved.

Another connection joint force type is a method in which both ends of a porous body are sandwiched between a polymer viscous adhesive layer and placed between the outer surface of a solid-state sound generating device and a free space plate to connect the free space plate. Therefore, the free space plate is used to loosely tighten the porous body (for example, bolts, etc.).
nut) and is tightened and fixed to the equipment wall.

Porous bodies are mainly lightweight (for example, specific gravity 0.2 to 1.5) and breathable materials that are synthetically molded from fibrous materials such as glass wool, rock wool, and slag wool, and inorganic or organic binders. It is.

This porous body can be used on its own, but it is also possible to use a porous body made by dividing the porous body into several parts and bonding the contact surfaces of each piece with a viscous polymeric adhesive. .

Due to the presence of the polymeric viscous adhesive layer, this porous body has the effect of improving vibration damping characteristics through energy conversion due to the strain effect of the adhesive layer, and contributing to the absorption of acoustic energy.

The thickness of the polymer viscous adhesive layer is preferably in the range of 0.2 to 2 mm.

The reason why a porous body is used as a joint is to take advantage of its remarkable difference in acoustic resistance and the rectifying wave effect due to its sound absorption properties.

Furthermore, the connecting joint force formula of the free space plate can be a combination of the above two connecting joint force formulas.

Next, we will discuss the vibration damping function of the connecting joint.

In both connection joints, free space plates are connected with a polymer viscous adhesive layer interposed between them, and vibrations are attenuated by converting energy due to strain in this polymer viscous adhesive layer, and the fitting of the connecting arms is also improved. The shape of the head can be formed into a shape that gives a volume change to vibration transmission, such as a cylindrical cross-section or a small-diamond shape, and the porous body can be made to have a diamond-shaped or circular cross-section, which gives a volume change to vibration transmission. , by creating a form in which the phase displacement and direction displacement of the vibration wave can be converted, a phase difference is caused in the vibration system due to a change in the transmission volume at the connection surface;
By providing a vibration damping effect, a synthetic wave is created and the vibration is suppressed. Due to the synergistic effect described above, the loss coefficient, which represents vibration damping, has been reduced to 0.5 or less in conventional soundproofing mechanisms. It is possible to achieve a high degree of vibration damping of 5 to 0.9.

Note that the connection joint can be firmly held against tertiary external forces such as wind pressure by fixing it to the wall of the solid-state sound generating device with bolts, nuts, etc.

Note that stud bolts can be easily installed in existing structures using the spot weld method when the mating material is a steel plate, or the gun driving method when the mating material is concrete.

The structure, operation, and effects of this invention will become clear from the description based on the accompanying drawings.

FIG. 3 shows a long connecting arm 2 having a fitting head 2a formed on the outer surface of a wall 1 of a solid-state sound generating device, the top of which has a cylindrical cross-sectional shape and a hollow rhombic shape for changing the volume for transmission of the vibration system. It is fixed by a method such as spot welding.

It is convenient that the fitting head 2a is formed by bending the top of the connecting arm 2 into a cylindrical shape or a hollow diamond shape.

A sound absorbing material 2b is filled in the hollow space of the fitting head 2a to absorb vibration noise.

The connecting arms 2 are provided in parallel at appropriate intervals.

A polymer viscous adhesive layer 3 is provided on each side surface between the opposing connecting arms 2.
A connecting skirt portion 4a, which is bent to match the shape of the side surface of the connecting arm 2, is fitted onto both side edges of the single free space plate 4 having a concave curved surface made of a metal plate.

The plate surface of the free space plate 4 is concavely curved, and due to the repulsive force of this curve, each connecting skirt portion 4a sandwiches the polymer viscous adhesive layer 3 on the side surface of the connecting arm 2, making it strong and airtight. It is fitted. Therefore, the fitted free space plate 4 can sufficiently withstand external pressure such as wind pressure.

To further withstand external pressure, tighten the connecting skirt and connecting arm with bolts and nuts.

FIG. 4 shows a connection mode of the Sandersch free space plate, in which the plate surface of the inner metal plate 4' is convexly curved, and its both side edges are bent to the connecting skirt part 4a', and the third
As shown in the figure, it is fitted onto the side surface of the connecting arm 2 via the polymer viscous adhesive layer 3, and further extends over the outer surface of the fitted inner metal plate 4' and the exposed surface of the fitting head 2a of the connecting arm. An example is shown in which a polymer viscous adhesive layer 4'' is provided, and an outer metal plate 4'' is further bonded to the surface of this adhesive layer to connect a free space plate 4s.

In the illustrated case, in order to facilitate the attachment of the outer metal plate 4'', it is divided into several pieces, and the adjoining parts of each are attached with heat-resistant tape 5 (for example, lead tape).

When this construction method is adopted, the outer plate 4'' is not limited to a metal plate, but also a non-metal plate can be bonded together, and the metal plate 4' and the non-metal plate 4'' can be connected as a sandwich free space plate.

Free air layer 6 formed by free space plates 4 and 4s
A sound absorbing material 7 is filled inside.

This free air layer 6 is divided into several sections by connecting arms 2 provided at appropriate intervals on the wall of the device.

The inventors refer to this divided free air space as a cellular free air space.

FIG. 5 shows an embodiment in which free space plates are connected by a connection joint made of a porous body. A transverse cut is made at the center, and the cut surfaces are bonded together with a polymer viscous adhesive layer 8a.

The porous body configured in this way is used as the wall body 9 of the solid-state sound generating device (
In the case shown, the hopper is shown).

This porous body has a through hole that becomes loose with the diameter of the tightening bolt, and a stud bolt 10 of a predetermined size is spot-welded and attached to the wall of the hopper, and the porous body is passed through this bolt. inserted through the hole.

At this time, a polymer viscous adhesive layer 11 is provided on the porous body and the hopper wall surface.

A single free space plate 12 is attached to the opposite surface of each porous body thus provided via a polymer viscous adhesive layer 11a.

Both side edges of the free space plate are bent inward to form bent portions 12d.

A sound absorbing material 14 is filled in each cell free air layer 13.

The free space plate 12 is tightened to the bolt 10 with a rubber washer 15, a washer 16, and a nut 17 in this order.

At this time, the end of the bent portion 12d of the free space plate is pressed against the polymer viscous adhesive layer 11' to keep the free air layer airtight.

Note that it is convenient to attach the sound absorbing material 14 to the back surface of the free space board 12 in advance.

The free space plate 12' in the figure is convexly curved, and is fitted into the hook-shaped bent portion of the adjacent free space plate via a polymer viscous adhesive layer 11b.

FIG. 6 shows the connection of the Sandermansch free space plates, and shows the inner plate 12b (
For example, a synthetic resin plate) is attached to the porous body 8 via a polymer viscous adhesive layer 11a, and then a polymer viscous adhesive layer 12e is attached to the porous body 8.
Except for attaching the outer plate 12a having the bent part 12d' between the parts and tightening it to the bolt according to the explanation in FIG.
Corresponding symbols appear in the same way as in FIG.

The inner and outer plates of the free-space plate with a curved surface of 125' are coated with a layer of polymeric viscous adhesive 1l at the hook-shaped bends of the corresponding plates.
It is fitted through b.

Other embodiments include using the molded porous body itself, or dividing the porous body into two or more parts and integrally forming a base with a viscous polymer adhesive, or using a metal having a bent part. Sandersch free space plates in which the inner and outer plates are metal plates or non-metallic plates, and also Sandercz free space plates with two or more layers of metal plates and non-metallic plates can also be connected using a connecting joint according to the above embodiment. .

According to the soundproofing structure of the present invention, acoustic waves generated from solid-state sound generating equipment are attenuated by opposing damping resonance, resistive damping, and rectifying wave action, thereby exhibiting excellent transmission loss and sound absorption properties, and at the same time exhibiting excellent transmission loss and sound absorption properties. By dividing and attenuating vibrations and suppressing them to an extreme extent, generation of secondary noise can be prevented and a soundproof structure with extremely high soundproofing effects can be obtained.

Furthermore, it is easy to install and can be easily installed according to each model.

[Brief explanation of drawings]

Figure 1 is a diagram of the experimental results showing the relationship between the installation of the free space plate and the transmission loss value, and Figure 2 is the diagram of the experimental results in which a sound absorbing material was inserted into the free air layer formed by the free space plate. ,
3 to 6 are cross-sectional views showing embodiments of the soundproof structure of the present invention. 1, 9... Device wall, 2... Connecting arm, 2a... Fitting head, 2b... Sound absorbing material,
3, 11, 11' 11a, 1lb... Polymer viscous adhesive layer, 4, 1 2, 1 2'... Single free space plate, 4a, 4a'... ...Connection skirt part, 1 2d, 12d'-...Bend part, 4s,
12s, 12s' Sanderutsch free space board, 4', 12
b...Inner plate, 4'', 12a...Outer plate, 4''', 12c...Polymer viscous adhesive layer,
5...Heat-resistant tape,...Sound absorbing material, adhesive layer, muwasha, 6,13...Free air layer, 7,14...8...
... Porous body, 8a ... Polymer viscosity 10
...Stud bolt, 15...Go16
...Washer 17...Nut.

Claims (1)

[Scope of Claims] 1. A solid-state sound generating device in which free-space plates with a gap formed on the outer surface of the device and the gap serving as a free air layer are connected by a connecting joint via a polymer viscous adhesive layer. Soundproof structure of equipment. 2. A soundproof structure for a solid-state sound generating device according to claim 1, wherein the free space plate is a single plate or a sandwich panel. 3. A soundproof structure for a solid-state sound generating device according to claim 1, wherein the free space plate has a flat or curved surface. 4. A soundproof structure for a solid-state sound generating device according to claim 1, wherein a sound absorbing material is filled in each of the free air layers divided into several sections by the connecting joint. 5. A soundproofing structure for a solid-state sound generating device according to claim 1, wherein the connecting joint has a fitting portion on the top of the arm body having a shape that imparts a volume change to vibration transmission. 6. A soundproof structure for a solid-state sound generating device according to claim 1, wherein the connecting joint is a porous body having a shape that imparts a volume change to vibration transmission. 7. A soundproof structure for a solid-state sound generating device according to claim 6, wherein the contact surfaces of both porous bodies are adhered with a viscous polymeric adhesive.