JPH08123440A - Sound absorbing structure of hall - Google Patents

Abstract

PURPOSE: To obtain a sound absorbing structure of a hall capable of controlling sound absorptivity according to a fluctuation in a specific frequency by composing a sound absorbing device of specific sound absorbing materials and voltage impressing means. CONSTITUTION: A front side weight part 54 is installed between the radiation end (b) of a first speaker 51 and the radiation end (c) of a second speaker 52 and a rear side superposing part 55 is installed between the radiation end (d) of the second speaker 52 and the radiation end (e) of a third speaker 53. The sound absorbing device 60 is installed over the entire surface of a floor 56 at the seats between the front side superposing part 54 and the rear side superposing part 55. This sound absorbing device 60 is composed of the sound absorbing materials having an electrosensitive (ENC) fluid compsns. for controlling sound wave absorption of and a variable sound source (voltage impressing means) connected to the sound absorbing materials. Further, the ENC fluid compsns. are formed by uniformly dispersing electric field arranging type (EA) particles which are solid particles into electrically insulatable media. The voltage of the prescribed value is impressed on the ENC fluid compsns. from the voltage impressing means when the frequency of the sounds of the specific frequency generated in the hall fluctuates.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound absorbing structure for so-called halls such as theaters, movie theaters, music halls, and stadiums.

[0002]

2. Description of the Related Art For example, in a music hall, there is a sound reproducing structure in which a plurality of or a plurality of sets of speakers share the sound emission range from the front side of the passenger seat to the rear side to transmit the performance sound to the entire passenger seat, In the sound emission range of each speaker, the overlapping portion is set so that no gap is created in the passenger seat. In the superimposing section, only the sound of a specific frequency resonates, so that the sound is likely to be amplified and reverberate too much, or conversely, the sound may be canceled and reduced. That is, this superposed portion is generated in the hole as a displaced portion of the sound of the specific frequency. Such a phenomenon can occur not only in the overlapping portion of the sound emission range of the speaker but also in a specific place depending on the shape of the wall and ceiling of the hall.

When the above-mentioned amplification or reduction of the sound of a specific frequency occurs in a specific place in a hall, the person sitting within the specific range is dissatisfied and the whole hall, which is generally called a whole tone, is called. It will spoil the sound. Therefore, conventionally, a sound absorbing structure as disclosed in, for example, Japanese Patent Publication No. 58-46040 is known. In this case, we have dealt with the phenomenon in which a specific frequency (high frequency) is significantly reduced in the superposed part of the sound emission range of the speaker. By lowering the sound absorption coefficient of the superposed part compared to other parts, the frequency is reduced. It is to flatten the characteristics. According to this structure, in order to reduce the sound absorption coefficient, the material of the floor, chair, etc. should be selected or the construction method should be changed so that the natural frequency matches the sound of the frequency to be absorbed, or the floor, chair The sound absorption coefficient is lowered by such means as making the shape such as an irregular shape where diffuse reflection is apt to occur as much as possible.

[0004]

However, according to the sound absorbing structure disclosed in the above publication, the sound absorption coefficient is higher than that of the other parts with respect to the floor, chair, etc. installed in the range corresponding to the overlapping portion of the sound emission range of the speaker. It takes a great deal of time and labor to design a structure that selects materials so that it will be low and changes the construction method, that is, that absorbs the sound of the frequency to be reduced, and the cost of hole construction costs. It is expected to bring up. Also, the sound of a specific frequency is
For example, it varies depending on environmental conditions and purpose of use of the hall. The environmental conditions in this case are climatic conditions such as temperature and humidity, the number of people in the hall, etc., and the purpose of use is a music concert where the main sound is a performance sound, or the main sound is a voice. Say the difference in sound quality, such as whether it is a debate. When the specific frequency fluctuates in this manner, the frequency of the sound to be reduced is determined in the above structure, and thus the fluctuating specific frequency sound cannot be reduced (sound absorption).

By the way, the inventors of the present invention have developed a fluid composition for electro-sensitive acoustic wave absorption control (hereinafter referred to as "Electric Noise-Control") having a novel electric field arrangement characteristic (hereinafter referred to as "EA characteristic") which has not been known. The fluid composition is abbreviated as “ENC fluid composition”). This ENC fluid composition is, for example,
It is a fluid obtained by dispersing solid particles in an electrically insulating medium.When an electric field is applied to this, the solid particles cause dielectric polarization, and the electrostatic attraction due to the dielectric polarization causes the solid particles to coordinate with each other in the electric field direction. Have the property of arranging and aligning to form a chain structure. In addition, some solid particles exhibit the property of exhibiting an array lump structure by electrophoresis and array alignment. In this way, the alignment orientation of the particles under the electric field is changed by the electric field alignment effect (hereinafter, referred to as Electric Alignment).
The nt effect is abbreviated as “EA effect”), and solid particles having such a property are referred to as electric field array particles (hereinafter,
The electric field arranging particles are abbreviated as “EA particles”). And the present inventors have found that the E of this novel structure is
The invention has been reached by advancing research into NC fluid compositions.

The present invention has been made in view of the above circumstances, and a sound absorbing device provided with an ENC fluid composition which has an EA effect and whose characteristic frequency can be changed by an applied voltage can be applied to a specific frequency fluctuation. It is an object of the present invention to provide a sound absorbing structure for a hall whose sound absorption coefficient can be adjusted accordingly.

[0007]

In order to achieve the above object, the sound absorbing structure for a hole according to claim 1 is a sound absorbing device for a hole in which a sound absorbing device is disposed at a displacement portion of a sound wave generated in the hole at a specific frequency. In the structure, the sound absorbing device comprises a sound absorbing material containing a fluid composition for electro-sensitive sound wave absorption control in which solid particles having an electric field array effect are contained in an electrically insulating medium, and the sound absorbing material. It is characterized by comprising a voltage applying means for applying a voltage to the electro-sensitive acoustic wave absorption controlling fluid composition and adjusting the applied voltage. The sound absorbing structure for a hall according to claim 2 is characterized in that, in the sound absorbing structure for a hall according to claim 1, the displacement part of the specific frequency of the sound wave is a superposed part in a sound emission range of a plurality of speakers. I am trying. The sound absorbing structure for a hole according to claim 3 is the sound absorbing structure for a hole according to claim 1, wherein the displacement portion of the specific frequency of the sound wave is
The feature is that it is a superposed part of the whole tone.

[0008]

According to the sound absorbing structure for a hole of the first aspect, the sound absorbing material of the sound absorbing device arranged at the displacement portion of the specific frequency generated in the hole reduces the sound of the specific frequency generated in the hole. Here, for example, when the frequency of the sound of a specific frequency generated in the hall fluctuates due to environmental conditions such as temperature, humidity, the number of people in the hall, or the purpose of use, the ENC which constitutes the sound absorbing material from the voltage applying means. A voltage of a predetermined value is applied to the fluid composition. By doing so, the sound absorbing frequency of the sound absorbing material changes, and the sound of the specific frequency that fluctuates depending on environmental conditions and purpose of use is reduced.

That is, the sound absorbing material has an EA effect in the ENC fluid composition when no voltage is applied.
The A particles are randomly suspended and dispersed in the electrically insulating medium. When a voltage is applied to the pair of electrode plates by the voltage applying means, the EA particles are arranged and linked in a chain shape to form a chain (particle chain).
Are formed, and the chains are arranged parallel to the electric field direction.
When a sound wave (air vibration) is applied to one of the electrode plates in this state, the electrode plate vibrates in the opposite direction, but the chain body itself has elasticity, so the chain body is stretched. When the particles are opposed to each other, they attract each other to generate an attractive force, and when they are compressed, they bend to generate a repulsive force, which causes a viscous resistance due to the movement of the chain in the electrically insulating medium, which causes a sound wave. Loss of energy (dissipation) occurs.

That is, the ENC fluid composition containing a chain resonates with the electrode plate due to the sound wave incident on the electrode plate. The sound wave frequency that gives vibration to such a chain is determined by the characteristic frequency of the chain (which is presumed to be the so-called natural frequency, which is the balance between the elasticity of the chain and the inertia of the electrode plate). When a sound wave having a frequency matching the characteristic frequency is incident on the electrode plate, the chain resonates and absorbs the sound wave, and sound waves of other frequencies are reflected. The attractive force acting on each particle (stress generated in the chain) increases as the voltage applied to the pair of electrode plates increases, so the elastic modulus and viscosity of the chain itself increase with the applied voltage. Therefore, the present invention utilizes this fact. In other words, by adjusting the applied voltage so that the characteristic frequency of the chain itself matches the frequency of the component of the incident sound wave (air vibration) that you want to remove, the chain resonates and absorbs sound. It consumes the energy of the component to be (removed) and reflects the other components.

FIG. 10 is a graph showing the results of measuring the effect of the electric field strength on the EA characteristics for a 30 wt% EA particle dispersion system. It is clear from this graph that the stress acting on the chain increases as the applied voltage increases. EA
The characteristic is that the dielectrically polarized particles are arranged in the direction of the electric field by an electric attraction to form a chain structure. At low shear rates, electrical attraction dominates, resulting in a gradual cycle of breaking and reforming chain structures. The yield stress is the force that is generated when a chain arranged in the direction of the electric field undergoes shear failure in the direction perpendicular to it. Considering that the particles of all chains formed have the same diameter and connect the electrode plates in a straight line, the number of chains is proportional to the particle concentration.
The yield stress will also be proportional to the particle concentration. FIG. 11 shows an equivalent circuit of the vibration system, that is, a coil spring 22 having an elastic modulus K and a dashpot 23 having a viscosity C are connected in parallel between a pair of electrode plates.

According to the sound absorbing structure for the hall of the second aspect, the sound of the specific frequency generated in the superposed portion in the sound emission range of the plurality of speakers is reduced, and the frequency of the sound to be reduced is changed by applying the voltage. It That is, the sound absorption coefficient is adjusted. Further, according to the sound absorbing structure for a hole of the third aspect, the sound of the specific frequency generated in the superimposed portion of the hole tones is reduced, and similarly, the frequency of the sound to be reduced is changed by applying the voltage.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the sound absorbing device of the present invention will be described below with reference to the drawings. FIG. 1 shows a side cross section of a music playing hall 40 to which the sound absorbing structure of this embodiment is applied. The hall 40 includes a stage 41, a first-floor passenger seat 42, and a second-floor passenger seat 4.
3, the ceiling 44, the side wall 45, and the like internally configure the ceiling 4
A spot chamber 45 is provided on the back side of 4, and a speaker installation section 46 is provided on the front side. The speaker installation unit 46 includes a plurality of first to third speakers 51, which are for middle and low sounds.
52 and 53 are installed, and in addition to these, a speaker for high sound (not shown) is installed. The first speaker 51 is in the range from a to b for the front side of the first-floor passenger seat 42, and the second speaker 52 is in the range from c to d for the rear side of the first-floor passenger seat 42 and the front side of the second-floor passenger seat 43. The speaker 53 of No. 3 is set to emit sound in the range from e to f for the rear side of the second floor passenger seat 43. That is, these first to third
The speakers 51, 52, and 53 are configured to share the sound emission range from the front side to the rear side of the passenger seats and transmit the performance sound to the entire passenger seats.

In the sound emission range of each speaker 51, 52, 53, a superimposing portion (displacement portion) is set so that no gap is created in the passenger seat. In this case, the first speaker 51
Between the radiating end b of the second speaker 52 and the radiating end c of the second speaker 52, and the rear overlapping part 55 between the radiating end d of the second speaker 52 and the radiating end e of the third speaker 52. Are set respectively. The front overlapping portion 54 is located at the rear of the first-seat passenger seat 42, and the rear overlapping portion 55 is located at the front of the second-seat passenger seat 43. Then, the sound absorbing device 60 is provided on the entire surface of the floor 56 in the passenger seats of the front side overlapping portion 54 and the rear side overlapping portion 55. As shown in FIGS. 2 and 3, the floor 56 includes a floor material 58 such as carpet or tile on the surface of a base 57.
The sound absorbing device 60 is disposed so as to be sandwiched between the base 57 and the floor material 58. And floor 5
A large number of chairs 59 are installed at 6. Sound absorbing device 60
Is composed of a sound absorbing material 61 having an ENC fluid composition and a variable power source (voltage applying means) 13 connected to the sound absorbing material 61.

The variable power source 13 includes a sound absorbing material 61.
The applied voltage is adjusted by applying a voltage to the ENC fluid composition constituting the above and rotating a knob (not shown). That is, according to the sound absorbing device 60 configured as described above, when the voltage is not applied from the variable power source 13, the sound of the sound absorbing frequency that matches the natural frequency of the floor 56 itself is reduced. When a voltage of a predetermined value is applied from, the sound of the frequency corresponding to the value of the applied voltage is reduced.

Next, the ENC fluid composition constituting the sound absorbing material 61 will be described. One example of an ENC fluid composition is shown in FIG. In this ENC fluid composition, EA particles 2 which are solid particles are uniformly dispersed in an electrically insulating medium 1. The EA particles 2 are composed of a core body 3 made of an organic polymer compound and a surface layer 5 made of particles 4 which are electric field aligning inorganic substances (hereinafter referred to as “EA inorganic substances”). Is forming. In this specific example, the electrically insulating medium 1 is colorless and transparent silicone oil, the organic polymer compound forming the core body 3 of the inorganic / organic composite particles is polyacrylic ester, and the EA inorganic substance forming the surface layer 5 is used. The particles 4 are white titanium hydroxide that is an inorganic ion exchanger and an electric semiconductor inorganic substance. The color of the EA particles (inorganic / organic composite particles) is, for example, white. The ratio of the EA particles 2 contained in the electrically insulating medium 1 is, for example, 7.5.
% By weight.

As shown in FIG. 7, this ENC fluid composition is interposed between a pair of electrode plates 7 and 8 which are spaced apart and arranged in parallel. As shown in FIG. 8, this pair of electrode plates 7,
When a voltage is applied to the power source 8 from the power source 9 through the switch 10, the EA particles 2 are arranged in a chain in a direction perpendicular to the surfaces of the electrode plates 7 and 8 due to the EA effect to form a chain body (particle chain) 6. Form. At this time, the chain-like bodies 6 are separated from each other and oriented in parallel.

Next, a sound wave absorption control device (sound vibration control device) using the above ENC fluid composition will be described.
As shown in FIG. 4, a pair of electrode plates 17 and 18 are opposed to each other with a gap (composition containing space) therebetween, and the EA effect of the present invention described above is provided between the pair of electrode plates 17 and 18. An ENC fluid composition containing the EA particles 2 contained therein in an electrically insulating medium 1 is contained. One (lower)
The electrode plate 18 is fixedly arranged on a fixing member (not shown), and the other electrode plate 17 is, for example, a PET (polyethylene terephthalate) film 17a that is flexible against sound waves.
Is evenly adhered to the lower surface of the. The pair of electrode plates 1
A frame-shaped sealing member 15 is fixed to the peripheral edges of the PET films 17a and 7 and 18.

The ENC fluid composition of the present invention is enclosed in a space defined by the pair of electrode plates 17 and 18 and the sealing member 15. The one electrode plate 17 and the PET film 17a have their peripheral edges fixed, but are configured so that they can be vibrated in the facing direction of the pair of electrode plates 17 and 18 (the vertical direction indicated by the arrow X). Accordingly, when the sound wave (air vibration) 11 is incident on the PET film 17a, the PET film 17a
The electrode plate 17a and one electrode plate 17 can vibrate vertically.

The variable power source 13 includes a pair of electrode plates 17 and 18
It is a power supply (voltage applying means) that applies a voltage between them and adjusts the applied voltage, and a switch 14 is connected in series to this power supply 13. By turning on the switch 14, a voltage can be applied between the pair of electrode plates 17 and 18. The sound wave absorption control device is usually in the form of a rectangular plate or a circular plate in appearance, but of course, it has an appropriate shape according to the place where it is installed.

Next, the operation of the sound wave absorption control device having the above configuration will be described. As shown in FIG. 4, a pair of electrode plates 1
When no voltage is applied between 7 and 18, ENC
The EA particles 2 of the fluid composition are randomly suspended and dispersed in the electrically insulating medium 1 (see FIG. 7). A pair of electrode plates 1
When a voltage is applied to 7, 18, E in the ENC fluid composition
The A particles 2 are arranged and linked in a chain to form a chain (particle chain) 6, and the chain 6 is arranged parallel to the electric field direction (see FIG. 8).

In this state, when a sound wave (air vibration) 11 is made incident on one of the electrode plates 17, (a), (b) of FIG.
The states of (c) and (d) occur sequentially, and the electrode plate 17 vibrates in the opposite direction as shown by the arrow X (see FIGS. 4 and 5) together with the PET film 17a. Due to its elastic nature, it is shown in FIG. 9 (b).
As shown in FIG. 9, when the chain-like body 6 is compressed, the chain-like body 6 bends in a V shape, for example, to generate a repulsive force.
As shown in, when the chain-like body 6 is pulled, the EA particles 2 facing each other attract each other to generate an attractive force. As a result, due to the movement of the chain-like body 6 in the ENC fluid composition, viscous resistance is generated and energy loss (dissipation) of the sound wave 11 occurs.

As the electrode plate 17 vibrates,
The chain 6 is repeatedly pulled and compressed,
As a result, the chain body 6 itself also vibrates. That is, the sound wave 11 incident on the electrode plate 17, the ENC fluid composition containing the chain body 6, the electrode plate 17 and the PET film 17
The electrode plate structure composed of a resonates. The sound wave frequency that gives vibration to the chain 6 is as follows.
When the sound wave 11 having a frequency that is determined by the characteristic frequency of the beam enters the electrode plate 17, the chain 17 resonates (see arrows A and B in FIG. 5) and absorbs the sound wave. , Sound waves 12 of other frequencies will be reflected.

The force acting between the EA particles 2 (stress generated in the chain 6) increases with an increase in the voltage applied to the pair of electrode plates 17 and 18, and therefore the elasticity of the chain 6 itself. The modulus and viscosity increase with increasing applied voltage. The present invention utilizes this fact to remove a desired component of a sound wave. That is, by adjusting the applied voltage,
By matching the characteristic frequency of the particle chains 6 with the frequency of the component (sound wave having a specific wavelength) to be removed in the sound wave (air vibration) incident on the electrode plate 17, as shown in FIG. The body 6 is caused to resonate by the action of the inertial force as indicated by the left and right arrows A and B, and the energy of the component of the incident sound wave 11 to be removed is consumed, while the other sound wave components (reference numeral 1) are consumed.
2) is reflected. In this way, the applied voltage can absorb the component of the desired specific wavelength of the incident sound wave.

The characteristic frequency of the sound wave absorption control device changes depending on the size of the EA particles (solid particles), the elastic force acting between the EA particles, the natural frequency of the electrode plates and the distance between the electrode plates. In this example, since spherical EA particles having a substantially uniform particle size were dispersed in the electrically insulating medium (without using irregular particles), the above-mentioned repulsive force and attractive force were not generated under a constant voltage. It does not fluctuate, and furthermore, the balance between the elastic force acting between the EA particles and the inertial force of the electrode plate does not fluctuate easily.
In the above-mentioned embodiment, the chain-like member is supposed to be bent in a V shape, but in addition to this, for example, FIG.
It is considered that there is a case where it is bent into an S-shape as shown in FIG. 4 or a W-shape as shown in FIG.

In the above embodiment, the phenomenon in which the EA particles (inorganic / organic composite particles) 2 form one row of chain-like bodies 6 and are arranged in parallel by the application of an electric field has been described. When the number of slabs exceeds several% by weight, 1
Instead of the chain bodies 6 in rows, the chain bodies 6 are joined to each other in a plurality of rows to form and arrange the columns 19 as shown in FIG. In this column 19, the left and right chain-shaped EA particles 2 are staggered by one and adjoin each other. With respect to this, the inventors of the present invention, as shown in FIG. 13B, have the EA particles 2 that are dielectrically polarized in the + pole portion and the − pole portion.
It is presumed that this is because it is more stable in terms of energy when the positive pole portion and the negative pole portion are alternately arranged adjacent to each other. Furthermore, although the ENC fluid composition is directly accommodated between the pair of electrode plates in the above-described embodiment, the present invention is not limited to this, and the porous body sufficiently impregnated with the ENC fluid composition is used as the pair of electrodes. It may be housed between the plates. In this case, the porous body preferably has open cells so as not to impair the EA effect.

Examples of the electrically insulating medium 1 used in the ENC fluid composition of the present invention include diphenyl chloride, butyl sebacate, aromatic polycarboxylic acid higher alcohol ester, halophenyl alkyl ether, trans oil, and the like.
Paraffin chloride, fluorinated oil, silicone oil, fluorosilicone oil, etc. have high electrical insulation and electrical breakdown strength, and are chemically stable and EA
Any fluid or a mixture thereof can be used as long as it can stably disperse the particles. This electrically insulating medium 1 can be colored according to the purpose. For coloring, it is preferable to use a type and amount of an oil-soluble dye or a dispersible dye that is soluble in the selected electrically insulating medium and does not impair its electrical properties. Electrically insulating medium 1
In addition to these, a dispersant, a surfactant, a viscosity modifier, an antioxidant, a stabilizer and the like may be contained.

The kinematic viscosity of this electrically insulating medium 1 is 1 cS.
It is preferably in the range of t to 30,000 cSt. When the kinematic viscosity is less than 1 cSt, the storage stability of the ENC fluid composition is insufficient, and the kinematic viscosity is 30,000 c.
If it is larger than St, it becomes difficult to uniformly disperse the EA particles, and it becomes difficult for the bubbles to be caught during the adjustment, and the bubbles will not come out easily, which is not preferable. From this viewpoint, the kinematic viscosity is preferably in the range of 10 cSt to 1000 cSt, particularly preferably in the range of 10 cSt to 100 cSt. Of course, the kinematic viscosity of the electrically insulating medium 1 changes with temperature, and this temperature effect can be suppressed by the applied voltage.

The EA particles 2 used in the present invention may be any element, organic compound, or inorganic compound, or a mixture thereof, as long as it is an inorganic-organic composite particle having an EA effect.
Either material can be used. Examples thereof include particles of inorganic ion exchangers, metal oxides, silica gel, inorganic substances having electric semiconductors, carbon black, and particles having these as a surface layer. However, this EA particle 2 is, as shown in the above example,
Inorganic / organic composite particles formed of a core 3 made of an organic polymer compound and a surface layer 5 made of EA inorganic particles 4 are particularly preferable. In this inorganic-organic composite particle, a core body 3 in which a surface layer 5 made of EA inorganic particles 4 having a relatively high specific gravity is an organic polymer compound having a relatively low specific gravity
The specific gravity of the particles as a whole can be adjusted so as to approximate to the electrically insulating medium 1. Therefore, the ENC fluid composition obtained by dispersing this in the electrically insulating medium 1 has excellent storage stability.

Examples of the organic polymer compound that can be used as the core 3 of the EA particles (inorganic / organic composite particles) 2 include poly (meth) acrylic acid ester, (meth) acrylic acid ester-styrene copolymer, Polystyrene, polyethylene, polypropylene, nitrile rubber, butyl rubber, AB
S resin, nylon, polyvinyl butyrate, ionomer, ethylene-vinyl acetate copolymer, vinyl acetate resin,
One or a mixture of two or more such as a polycarbonate resin or a copolymer may be mentioned.

Particles 4 of EA inorganic material forming the surface layer 5
Although various compounds can be used, preferred examples include inorganic ion exchangers, silica gel, and electrically semiconducting inorganic substances. When these particles 4 are used to form the surface layer 5 on the core 3 made of an organic polymer compound, the obtained inorganic / organic composite particles become useful EA particles 2.

Examples of the above inorganic ion exchanger include (1)
Hydroxide of polyvalent metal, (2) hydrotalcites,
(3) Acid salt of polyvalent metal, (4) Hydroxyapatite, (5) Nasicon type compound, (6) Clay mineral, (7)
Mention may be made of potassium titanates, (8) heteropolyacid salts, and (9) insoluble ferrocyanide.

The respective inorganic ion exchangers will be described in detail below. (1) Hydroxide of polyvalent metal. These compounds are represented by the general formula MOx (OH) y (M is a polyvalent metal, x is a number of 0 or more, and y is a positive number), and examples thereof include titanium hydroxide and zirconium hydroxide. ,
Examples include bismuth hydroxide, tin hydroxide, lead hydroxide, aluminum hydroxide, tantalum hydroxide, niobium hydroxide, molybdenum hydroxide, magnesium hydroxide, manganese hydroxide, and iron hydroxide. Here, for example, titanium hydroxide refers to hydrous titanium oxide (also known as metatitanic acid or β-titanic acid, Ti
It contains both O (OH) ₂ ) and titanium hydroxide (also known as orthotitanic acid or α-titanic acid, Ti (OH) ₄ ), and the same applies to other compounds.

(2) Hydrotalcites. These compounds have the general formula M ₁₃ Al ₆ (OH) ₄₃ (C
O) ₃ · 12H ₂ O (M is a divalent metal),
For example, the divalent metal M is Mg, Ca or Ni. (3) Acid salt of polyvalent metal. These are, for example, titanium phosphate, zirconium phosphate, tin phosphate, cerium phosphate, chromium phosphate, zirconium arsenate, titanium arsenate, tin arsenate, cerium arsenate, titanium antimonate, tin antimonate, tantalum antimonate. , Niobium antimonate, zirconium tungstate, titanium vanadate, zirconium molybdate, titanium selenate, and tin molybdate.

(4) Hydroxyapatite. These are, for example, calcium apatite, lead apatite,
Examples include strontium apatite and cadmium apatite. (5) Nasicon type compound. These include, for example, (H ₃ O) Zr ₂ (PO ₄ ) ₃ but in the present invention, a Nasicon type compound in which H ₃ O is replaced with Na can also be used. (6) Clay mineral. These are, for example, montmorillonite, sepiolite, bentonite and the like, with sepiolite being particularly preferred.

(7) Potassium titanates. These general formula _{aK 2 O · bTiO 2 · nH} 2 O (a 0
<A is a positive number that satisfies a ≦ 1, b is a positive number that satisfies 1 ≦ b ≦ 6, and n is a positive number), for example, K ₂ ·
TiO ₂ · 2H ₂ O, K ₂ O · 2TiO ₂ · 2H ₂ O, 0.
5K ₂ O ・ TiO ₂・ 2H ₂ O, and K ₂ O ・ 2.5TiO
₂ · 2H ₂ O, and the like. In addition, among the above compounds, a compound in which a or b is not an integer is easily synthesized by subjecting a compound in which a or b is an appropriate integer to an acid treatment and replacing K with H.

(8) Heteropolyacid salt. These are represented by the general formula H ₃ AE ₁₂ O ₄₀ .nH ₂ O (A is phosphorus, arsenic, germanium, or silicon, E is molybdenum, tungsten, or vanadium, and n is a positive number), For example, ammonium molybdophosphate and ammonium tungstophosphate. (9) Insoluble ferrocyanide. These are compounds represented by the following general formula. Mb-pxa
A [E (CN) ₆ ] (M is an alkali metal or hydrogen ion, A is a heavy metal ion such as zinc, copper, nickel, cobalt, manganese, cadmium, iron (III) or titanium, E is iron (II), iron (III), cobalt (II) or the like, b is 4 or 3, a is a valence of A, and p is a positive number of 0 to b / a.) These include, for example, Cs. Insoluble ferrocyanine compounds such as ₂ Zn [Fe (CN) ₆ ] and K ₂ Co [Fe (CN) ₆ ] are included.

The inorganic ion exchangers (1) to (6) each have an OH group, and some or all of the ions present at the ion exchange sites of these inorganic ion exchangers are different from other ions. Those substituted with (hereinafter, referred to as a substitutional inorganic ion exchanger) are also included in the inorganic ion exchanger of the present invention. That, R-M ¹ inorganic ion exchanger described above (M ¹ represents an ion species of the ion exchange sites) is expressed as a part or all of M ¹ in the R-M ^1, the ion exchange reaction below A substituted inorganic ion exchanger in which an ionic species M ² different from M ¹ is substituted by
It is an inorganic ion exchanger in the present invention. xR−M ¹ + yM ² → Rx− (M ² ) y + xM ¹ (where x and y represent the valences of the ion species M ² and M ¹ , respectively). M ¹ varies depending on the type of the inorganic ion exchanger having an OH group, but when the inorganic ion exchanger exhibits a cation exchange property, M ¹ is generally H ⁺ , and in this case, M ² is an alkali metal or an alkali. Any metal ion other than H ⁺ , such as earth metals, polyvalent typical metals, transition metals or rare earth metals. When the inorganic ion exchanger having an OH group exhibits anion exchange property, M ¹ is generally OH ^−.
Where M ² is, for example, I, Cl, SCN, N
Any of anions other than OH ⁻ such as O ₂ , Br, F, CH ₃ COO, SO ₄ or CrO ₄ and complex ions.

Further, regarding the inorganic ion exchanger which has once lost the OH group due to the high temperature heat treatment but becomes to have the OH group again by an operation such as immersion in water, the inorganic ion after the high temperature heat treatment is used. Exchangers and the like are also a kind of inorganic ion exchangers that can be used in the present invention, and specific examples thereof include a Nasicon type compound such as (H ₃ O) Zr ₂
(PO ₄₎ HZr ₂ obtained by heating ₃ (PO _{4) 3} and high-temperature heat treatment of hydrotalcite (500 to 70
Heat treated at 0 ° C.) and the like. These inorganic ion exchangers can be used not only in one kind but also in many kinds simultaneously as a surface layer. It is particularly preferable to use a hydroxide of a polyvalent metal and an acid salt of a polyvalent metal as the above-mentioned inorganic ion exchanger.

An example of an electrically semiconductive inorganic material that can be used as the surface layer 5 of the EA particles (inorganic / organic composite particles) 2 is a metal having an electric conductivity of 10 ³ to 10 ^-11 Ω ^-1 / cm at room temperature. Oxides, metal hydroxides, metal oxide hydroxides, inorganic ion exchangers, or metal-doped at least one of these, or at least any one of these regardless of the presence or absence of metal doping For example, those applied as an electric semiconductor layer on another support.

Examples of preferable electrically semiconductive inorganic substances are shown below. (A) Metal oxide: For example, SnO ₂ or amorphous titanium dioxide (manufactured by Idemitsu Petrochemical Co., Ltd.). (B) Metal hydroxide: For example, titanium hydroxide or niobium hydroxide. Here, titanium hydroxide means hydrous titanium oxide (manufactured by Ishihara Sangyo Co., Ltd.), metatitanic acid (also known as β-titanic acid,
TiO (OH) ₂ ) and orthotitanic acid (also known as α-titanic acid, Ti (OH) ₄ ) are included. (C) Metal oxide hydroxide: For example, FeO
(OH) (goethite) and the like can be mentioned. (D) Hydroxide of polyvalent metal: equivalent to inorganic ion exchanger (1). (E) Hydrotalcites: Inorganic ion exchanger (2)
Equivalent to (F) Acid salt of polyvalent metal: equivalent to the inorganic ion exchanger (3). (G) Hydroxyapatite: Inorganic ion exchanger (4)
Equivalent to (H) Nashicon type compound: equivalent to the inorganic ion exchanger (5). (I) Clay mineral: equivalent to the inorganic ion exchanger (6). (J) Potassium titanate: equivalent to the inorganic ion exchanger (7). (K) Heteropolyacid salt: equivalent to the inorganic ion exchanger (8). (L) Insoluble ferrocyanide: equivalent to inorganic ion exchanger (9). (M) Metal-Doped Electric Field Alignment Inorganic Material: This is an ER inorganic material doped with a metal such as antimony (Sb) in order to increase the electric conductivity of the above-mentioned electric semiconductor inorganic materials (A) to (L). As an example, antimony (Sb) -doped tin oxide (SnO ₂ ) and the like can be mentioned. (N) EA inorganic material applied as an electric semiconductor layer on another support: for example, titanium oxide, silica as a support,
Examples thereof include inorganic particles such as alumina and silica-alumina, or organic polymer particles such as polyethylene and polypropylene, to which antimony (Sb) -doped tin oxide (SnO ₂ ) is applied as an electric semiconductor layer. . The particles in which the EA inorganic substance is applied to the other support as described above can be regarded as the EA inorganic substance as a whole. These EA minerals are not only one type, but two
It is also possible to use types or more simultaneously as the surface layer.

The EA particles (inorganic / organic composite particles) 2 can be manufactured by various methods. For example, there is a method in which a particulate core body 3 made of an organic polymer compound and fine particulate particles 4 are transported by a jet stream and collided with each other to produce them. In this case, the fine particles of the particles 4 collide with the surface of the particulate core 3 at a high speed and are fixed to form the surface layer 5. Another example of the manufacturing method is a method in which the particulate core body 3 is suspended in a gas, and a solution of the particles 4 is atomized and sprayed on the surface. In this case, the surface layer 5 is formed by adhering the solution onto the surface of the core 3 and drying it.

A particularly preferred method for producing the EA particles (inorganic / organic composite particles) 2 is a method of forming the surface layer 5 at the same time as the core body 3. In this method, for example, when emulsion-polymerizing, suspension-polymerizing, or dispersion-polymerizing a monomer of an organic polymer compound that forms the core body 3 in a polymerization medium, particles 4 which are fine particle EA inorganic substances in the above-mentioned monomer, Alternatively, it is present in the polymerization medium. Water is preferred as the polymerization medium, but a mixture of water and a water-soluble organic solvent can also be used, and an organic poor solvent can also be used. According to this method, the monomers are polymerized in the polymerization medium to form the core particles 3, and at the same time, the fine particle EA inorganic particles 4 are layered on the surface of the core 3 to cover the core particles 3. The surface layer 5 is formed.

In the case of producing EA particles (inorganic / organic composite particles) by emulsion polymerization or suspension polymerization, the EA inorganic particles 4 are combined by combining the hydrophobic property of the monomer and the hydrophilic property of the EA inorganic substance. Can be attached to the surface of the core body 3. According to the method of simultaneously forming the core body 3 and the surface layer 5, the EA inorganic particles 4 are densely and firmly adhered to the surface of the core body 3 made of an organic polymer compound, and the EA particles (inorganic / organic composite) Particles 2) are formed.

The shape of the EA particles 2 used in the present invention does not necessarily have to be spherical, but when the particulate core 3 is produced by the controlled emulsion / suspension polymerization method, the EA particles obtained are obtained. The shape of the particles 2 is almost spherical. EA
The particle size of the particles 2 is not particularly limited, but is 0.1
The thickness is preferably in the range of μm to 500 μm, particularly 5 μm to 200 μm. Fine particle EA at this time
The particle size of the inorganic particles 4 is not particularly limited, but is preferably 0.005 μm to 100 μm, and more preferably 0.01 μm to 10 μm.

In the EA particle (inorganic / organic composite particle) 2, the particle 4 and the core 3 which are the EA inorganic material forming the surface layer 5 are formed.
The weight ratio of the organic polymer compound forming the is not particularly limited, but in order to obtain an ENC fluid composition having high storage stability, the EA inorganic particles 4 and the organic polymer compound core 3 are used. 1% by weight of particles 4 to 6% of the total weight
It is preferably in the range of 0% by weight, particularly preferably in the range of 4% by weight to 30% by weight. If the proportion of the core 3 is less than 1% by weight, the EA characteristics of the obtained EA particles 2 will be insufficient, and if it exceeds 60% by weight, the specific gravity of the EA2 particles will be excessive and the storage stability may be impaired. There is. Further, the ENC fluid composition of the present invention can be produced by uniformly stirring and mixing the above-mentioned EA particles 2 together with a dispersant and other components in an electrically insulating medium. As the stirrer, any stirrer normally used for dispersing solid particles in a liquid dispersion medium can be used. In an electrically insulating medium 1
The content of the EA particles 2 in is not particularly limited, but is preferably 0.5 to 75% by weight, and particularly preferably 5 to 50% by weight. If the content is less than 1%, a sufficient EA effect cannot be obtained, and if the content is 75% or more, the initial viscosity of the ENC fluid composition when a voltage is not applied becomes too large, which makes it difficult to use.

The EA particles 2 produced by the above various methods, particularly the method of simultaneously forming the core 3 and the surface layer 5,
The whole or part of the surface layer 5 may be covered with a thin film of an organic polymer substance, a dispersant used in the manufacturing process, an emulsifier or other additive substances, and the EA effect as EA particles may not be sufficiently exhibited. . This thin film of inert material can be easily removed by polishing the surface of the particles. Therefore, when the core body 3 and the surface layer 5 are simultaneously formed, it is preferable to polish the surfaces thereof.

The surface of the particles can be polished by various methods. For example, E, which is an inorganic / organic composite particle
The A particles 2 can be dispersed in a dispersion medium such as water and then stirred. At this time, the EA particles 2 are mixed with an abrasive such as sand particles or balls in the dispersion medium.
It can also be carried out by a method of stirring together with it, or a method of stirring by using a grinding wheel. For example again
It is also possible to carry out dry stirring without using the dispersion medium, using the EA particles 2 and the above-mentioned abrasive or grinding wheel.

A more preferable polishing method is a method in which the EA particles 2 are agitated by a jet stream or the like. This is a method of polishing particles by violently colliding with each other in a gas phase, and is a preferable method in that the polished particles can be easily separated by classification without the need for another abrasive. In the above jet stream agitation, it is necessary to select polishing conditions depending on the type of equipment used, the agitation speed, the material of the EA particles 2, etc., but generally 60
It is preferable to perform jet stream stirring at a stirring speed of 00 rpm for about 0.5 min to 15 min.

The ENC fluid composition of the present invention comprises an EA as described above.
The particles 2 can be produced by uniformly stirring and mixing them in the electrically insulating medium 1 together with other components such as a dispersant, if necessary. As the stirrer, any stirrer normally used for dispersing solid particles in a liquid dispersion medium can be used.

As described above, according to the hole 40 in which the sound absorbing device 60 of this embodiment is arranged in the front superimposing portion 54 and the rear superimposing portion 55, the sound absorbing device 60 absorbs the sound absorbing frequency (sound absorbing frequency) of the floor 56. By properly adjusting the ratio, the amplification (excessive reverberation) or reduction (cancellation) of the sounds generated in the superimposing units 54 and 55 is eliminated, and the frequency characteristics are flattened. In other words, the sound absorption rate is increased when the sound is too reverberant, and the sound absorption rate is decreased when the cancellations occur. When the specific frequency changes in the front superimposing part 54 and the rear superimposing part 55 due to environmental conditions such as temperature, humidity, the number of people in the hall, or the purpose of use with different sound quality, if the specific frequency changes, Sound absorbing material 61
Can be adjusted by. That is, in this case, by applying the voltage from the variable power source 13 to the sound absorbing material 61 while adjusting the voltage, and by adjusting the frequency at which the sound absorbing material 61 can absorb sound to the undesired specific frequency that fluctuates depending on environmental conditions, it is possible to specify very easily. The sound absorption coefficient of the frequency sound can be adjusted. That is, it is possible to properly adjust the sound of an undesired specific frequency, which fluctuates due to various factors such as environmental conditions and purpose of use, by changing the value of the voltage applied to the sound absorbing material 61. Can be brought into an acoustically excellent state.

Further, as in the conventional case, for the floor 56 and the chair 59 installed in the range corresponding to the overlapping portions 54 and 55, the material is selected so that the sound absorption coefficient is lower than that of other portions,
Since there is no need to change the construction method, and the sound absorbing material 61 is installed between the base 57 and the floor material 58 that form the floor 56, and the variable power source 13 is connected to the sound absorbing material 61, the structure can be carried out in a hall. It is possible to reduce the construction cost.

In the above embodiment, the sound absorbing device 60 is arranged on the floor 56 of the overlapping portions 54 and 55 in the sound radiation range of the first, second and third speakers 51, 52 and 53 in the hall 40. However, the structure is to appropriately adjust the undesired specific frequency generated in the superimposing portions 54 and 55.
The present invention can also be applied to a superposed portion where a hall tone, which is a characteristic sound of the hall 40, reverberates too much. The overlapping portion of the hall tone is specified by the shapes of the side wall 45 and the ceiling 44 of the hall, and the sound absorbing device 60 similar to the above is disposed in the portion corresponding to the overlapping portion of the side wall 45 and the ceiling 44. As a result, excessive reverberation of the hall tone can be suppressed, and the sound reverberating in the entire hall 40, that is, the hall tone can be brought into an extremely preferable state.

In other words, according to the present invention, by disposing a sound absorbing device such as the sound absorbing device 60 in the displacement portion of the sound wave generated in the hall at the specific frequency, even if the environmental condition or the purpose of use varies. Even if the specific frequency fluctuates, the sound absorption coefficient of the displacement part of the specific frequency is adjusted by changing the voltage applied to the ENC fluid composition of the sound absorbing device according to the fluctuation, and the undesirable sound generated in the hall is suppressed. It can be removed.

[0055]

As described above, according to the sound absorbing structure of the hole of the present invention, the following effects can be obtained.
According to the sound absorbing device according to claim 1, for example, a change occurs in the specific frequency in the displacement section of the specific frequency due to environmental changes such as temperature, humidity, the number of people in the hall, and the purpose of use with different sound quality. Also, since the sound absorption frequency can be changed by applying a voltage of a predetermined value to the ENC fluid composition constituting the sound absorbing material by the voltage applying means, it is possible to surely adjust the sound of the fluctuating specific frequency. The inside can be in a good acoustic state. In addition, since the structure of the sound absorbing device itself is simple and only the sound absorbing device is arranged on the floor, wall, and ceiling of the overlapping portion, the cost of constructing the hall can be reduced.

According to the sound absorbing structure of the second aspect, it is possible to properly adjust the sound absorbing coefficient in the overlapping portion in the sound emission range of the plurality of speakers in the hole. According to the sound absorbing structure of the third aspect of the present invention, it is possible to properly adjust the sound absorbing coefficient in the hole tone overlapping portion in the hole.

[Brief description of drawings]

FIG. 1 is a side sectional view of a hole to which a sound absorbing structure according to an embodiment of the present invention is applied.

FIG. 2 is a side sectional view showing a state in which the sound absorbing device of the embodiment is arranged on the floor of a hall.

FIG. 3 is a side sectional view of the relevant part.

FIG. 4 is a cross-sectional view of a sound wave absorption control device (sound control device) provided with a fluid composition for electrosensitive sound wave absorption control.

FIG. 5 is a cross-sectional view showing a state in which a chain and one of the electrode plates are resonating upon incidence of a sound wave in the sound wave absorption control device.

FIG. 6 is a cross-sectional view showing an example of the fluid composition for electro-sensitive sound wave absorption control according to the present invention.

FIG. 7 is a cross-sectional view showing an aspect of the fluid composition for electro-sensitive sound wave absorption control according to the present invention when the power is off.

FIG. 8 is a cross-sectional view showing a mode of the fluid composition for electro-sensitive sound wave absorption control according to the present invention when the power is turned on.

FIG. 9 is a cross-sectional view showing a state where a sound wave is incident on the sound wave absorption control device and one of the electrode plates vibrates.

FIG. 10 is a graph showing the results of measuring the effect of electric field strength on electric field arrangement characteristics of an electric field arrangement particle dispersion system.

FIG. 11 is a diagram showing an equivalent circuit of a vibration system.

FIG. 12 is a diagram showing another example of the bending state of the chain in the sound wave absorption control device.

FIG. 13 is a view showing a column in which a plurality of chains are joined to each other in the sound wave absorption control device.

[Explanation of symbols]

1 ... Electrically insulating medium, 2 ... EA particles (solid particles), 13
... variable power source (voltage applying means), 40 ... hall, 46 ... speaker installation section, 51 ... first speaker, 52 ... second speaker, 53 ... third speaker, 54 ... front side superposition section (displacement section), 55 ... Rear side overlapping part (displacement part), 56 ... Floor, 60
Sound absorbing device, 61 Sound absorbing material.

Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location G10K 15/00 G10K 15/00 M (72) Inventor Moritaka Goto 1-5-1 Kiba, Koto-ku, Tokyo Stocks In Fujikura (72) Inventor Kenji Furuichi 1-5-1, Kiba, Koto-ku, Tokyo In Fujikura Co., Ltd. (72) In Yasufumi Otsubo 9-21-1 Nakanakadai, Inage-ku, Chiba, Chiba 206

Claims (3)

[Claims] 1. A sound absorbing structure for a hole, wherein a sound absorbing device (60) is arranged at a displacement portion (54, 55) of a specific frequency of a sound wave generated in the hole (40).
0) is a sound absorbing material (61) containing a fluid composition for electro-sensitive sound wave absorption control in which solid particles (2) having an electric field arrangement effect are contained in an electrically insulating medium (1), A hole comprising a sound absorbing material (61) and voltage applying means (13) for applying a voltage to the fluid composition for electro-sensitive sound wave absorption control and adjusting the applied voltage. Sound absorption structure. 2. A displacement part (54,
55. The sound absorbing structure for a hall according to claim 1, wherein 55) is a superposed portion in a sound emission range of the plurality of speakers. 3. The sound absorbing structure for a hall according to claim 1, wherein the displacement portion of the specific frequency of the sound wave is a superposition portion of the hall tone.