JPH08156712A - Vehicle sound wave absorption control device vehicle equipped with it, and, vehicle sound wave absorption control method - Google Patents

Abstract

PURPOSE: To provide a vehicle sound wave absorption control device equipped with an electrically responsive type sound wave adsorption controlling fluid compound and a method of controlling absorption of vehicle sound waves. CONSTITUTION: An electrically responsive type sound wave absorption control device 10 is composed of an electrically responsive sound absorption control fluid compound in which solid particles having an field arranged effect are contained in an electrically insulating medium, electrode plates 3, 4 which are spaced from each other and opposed to each other, and a variable power source 6 for applying a desired voltage between the electrode plate 3, 4. Accordingly, a desired voltage is applied to the electrode plates 3, 4 so as to arrange the solid particles in order to absorb sound waves in a specific frequency range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a vehicle acoustic wave absorption control device provided with an electro-sensitive type acoustic wave absorption control fluid composition capable of controlling a characteristic frequency based on an electric field array effect. The present invention relates to a vehicle and a sound wave absorption control method for the vehicle.

[0002]

2. Description of the Related Art Usually, a driver of a car receives various vibrations and sounds,
For example, friction noise between a tire and a road during traveling, horns of other vehicles, engine sounds leaking from the engine room of the own vehicle and other vehicles, etc. are heard as noise. In particular, the engine has a mechanism that burns and explodes fuel such as gasoline and light oil, and because it is the drive source of the vehicle, the engine noise always echoes in the vehicle, and in some cases, these sounds are transmitted to the surroundings. The noise of the car has caused problems such as a decrease in the comfort of the environment inside the vehicle.

Therefore, conventionally, in order to reduce the noise leaking from the engine room, a sound absorbing material such as a damping steel plate has been attached to the engine room or parts constituting the engine. The damping steel plate has a sandwich structure in which elastic resins such as polyester or polyethylene are sandwiched between steel plates. Such damping steel sheets are used for interior panels such as dash panels that form an engine room, or for oil pans that are a type of parts that form an engine. In such a vibration-damping steel plate, when bending vibration is applied to the steel plate, the resin layer made of resin sandwiched between the steel plates undergoes shear deformation and the vibration energy is converted into heat energy, thereby reducing noise. To be done.

[0004]

However, since the conventional acoustic wave absorber has a constant natural frequency depending on its material,
Only absorbs (removes) sound waves of components that match its natural frequency
When it is not possible to change the component of the sound wave to be absorbed, it is necessary to replace the sound wave absorbing material with a different material corresponding to the frequency of the sound wave. In particular, for those whose frequency changes depending on the speed of the vehicle, strictly speaking, the number of revolutions of the engine, such as engine sound, a predetermined sound wave absorbing material corresponding to the frequency of the sound wave component to be absorbed. However, it is practically difficult to convert the material of the sound wave absorber once installed in the engine room into the optimum material according to the frequency of the engine sound during running. there were.

By the way, the inventors of the present invention have proposed an electro-sensitive acoustic wave absorption control fluid composition (hereinafter referred to as “Elect”) having a novel electric field arrangement characteristic (abbreviated as EA characteristic) which has not been known so far.
ric Noise-Control fluid composition is abbreviated as “ENC fluid composition”).
This ENC fluid composition is, for example, a fluid obtained by dispersing solid particles in an electrically insulating medium, and when a voltage is applied to the solid particles, the solid particles cause dielectric polarization, and further electrostatic attraction due to the dielectric polarization causes It has the property of forming a chain structure by aligning and aligning in the direction of the electric field. In addition, some solid particles may be electrophoresed and arrayed to exhibit an arrayed lump-like structure. As described above, the arrangement of particles under an electric field can be changed by the electric field arrangement effect (hereinafter, referred to as “Select”).
“RIC effect” is abbreviated as “EA effect”
Solid particles having such properties are referred to as electric field array particles (hereinafter abbreviated as EA particles). Then, the present inventors arrived at the present invention by advancing research on the ENC fluid composition having this novel structure.

The present invention has been made in view of the above problems of the prior art, and has a EA effect and a sound wave for vehicles provided with an ENC fluid composition capable of changing a characteristic frequency by an applied voltage. An object of the present invention is to solve the above problems by providing an absorption control device, a vehicle equipped with the same, and a vehicle sound wave absorption control method.

[0007]

An object of the present invention is to provide a vehicle acoustic wave absorption control device provided in an engine room of a vehicle, wherein an ENC fluid containing solid particles having an EA effect in an electrically insulating medium. A composition, a pair of electrode plates provided facing each other with a gap and containing the ENC fluid composition in the gap, and a power supply for applying a desired voltage between the pair of electrode plates. This can be achieved by the vehicle sound wave absorption control device. Further, the vehicle sound wave absorption control device may be provided outside an interior panel forming an engine room.

Further, the solid particles are formed of a core body made of an organic polymer compound and a surface layer containing an electric field aligning inorganic substance (hereinafter, EA inorganic substance) which is an inorganic substance having an EA effect. It is a composite particle. further,
The EA inorganic substance is at least one selected from the group consisting of an inorganic ion exchanger, silica gel, and an electric semiconductor inorganic substance. The concentration of the solid particles in the electric insulator medium is in the range of 0.5 to 75% by weight.

When the EA inorganic substance is an inorganic ion exchanger, the inorganic ion exchanger includes hydroxides of polyvalent metals, hydrotalcites, acid salts of polyvalent metals, hydroxyapatite, Nasicon type compounds, clay minerals. It is preferably at least one selected from the group consisting of, potassium titanates, heteropolyacid salts and insoluble ferrocyanides.

When the EA inorganic substance is an electric semiconductor inorganic substance, the electric semiconductor inorganic substance is 10 ³ at room temperature.
It is preferable to Omega ^-1 cm ^-1 not those having an electric conductivity in the range of 10 ^-11 Ω ^-1 cm ^-1. This electrically semiconductive inorganic substance is a metal oxide, a metal hydroxide, a metal oxide hydroxide, an inorganic ion exchanger, a metal-doped one or more of these, and whether or not metal-doped. , At least one of these 1
It is preferably at least one selected from the group consisting of a seed applied on another support as an electric semiconductor layer.

The vehicle sound wave absorption control method of the present invention is based on EN
A voltage is applied to the C fluid composition to form particle chains of the EA particles. Further, the applied voltage may be appropriately adjusted by a variable power source. Further, a predetermined voltage may be applied by a fixed power source whose optimum voltage is adjusted in advance. Further, a porous body impregnated with the ENC fluid composition may be provided between the electrode plates. Further, in order to manufacture a vehicle having an excellent sound insulation effect, it is preferable to install the vehicle sound wave absorption control device in an engine room in the vehicle.

[0012]

In the vehicle sound wave absorption control apparatus of the present invention, when the voltage is not applied between the pair of electrode plates, EN
The EA particles in the C-fluid composition are randomly suspended and dispersed in the electrically insulating medium. When a desired voltage is applied to the pair of electrode plates by a variable power source or a fixed power source, the EA
Particles are arrayed and linked in a chain to form a chain (particle chain),
The chains are arranged parallel to the electric field direction. In this state, if a sound wave (air vibration) is applied to one of the electrode plates,
This electrode plate vibrates in the opposite direction, but since the chain itself has elasticity, when the chain is pulled, when the particles facing each other attract each other, the attractive force is compressed. Bends to generate a repulsive force, and a viscous resistance is generated by the movement of the chain in the electrically insulating medium, which causes a loss (dissipation) of the energy of the sound wave.

That is, the ENC fluid composition containing the 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.

Since the attractive force (stress generated in the chain) acting between the particles increases as the voltage applied to the pair of electrode plates increases, the elastic modulus and viscosity of the chain itself are applied. The present invention takes advantage of this as the voltage increases as the voltage increases. 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. 15 is a graph showing the results of measuring the effect of the electric field strength on the EA characteristics of a solid EA particle 30 wt% dispersion system. It is clear from this graph that the stress acting on the chain increases as the applied voltage increases. E
The characteristic A is due to the particles that have been dielectrically polarized arranged in the direction of the electric field due to an electric attraction to form a chain structure. At low breaking speeds, the electric attraction is dominant, so that the chain structure is gradually broken and reformed repeatedly. 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. 16 shows an equivalent circuit of the vibration system of the present invention, 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.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case where an engine is mounted in front of a vehicle body will be described below as an example of a vehicle sound wave absorption control apparatus of the present invention. As shown in FIG. 1, this vehicle acoustic wave absorption control device includes a pair of films 1 and 2 arranged to face each other with a gap, and electrode plates 3 and 4 are provided inside the films 1 and 2, respectively. Between the pair of electrode plates 3 and 4, E
An ENC fluid composition 40 containing EA particles having an A effect in an electrically insulating medium is contained. A frame-shaped seal member 5 is fixed to the peripheral edges of the pair of electrode plates 3 and 4 and the peripheral edges of the pair of films 1 and 2 so that the ENC fluid composition 40 does not flow out.

Further, each of the electrode plates 3 and 4 is a power source 6 (variable power source) capable of applying a voltage and varying the applied voltage.
It is connected to the. A switch 7 is connected in series to the power source 6, and when the switch 7 is turned on, a voltage is applied between the pair of electrode plates 3 and 4, and the switch 7 is turned on.
The application of voltage can be stopped by turning off. The switch 7 is linked with an ignition switch. Further, a variable knob (not shown) is connected to the power source 6, and the applied voltage value can be adjusted by twisting the variable knob.

The vehicle sound wave absorption control apparatus 10 described above is
As shown in FIGS. 2 to 4, it is provided on the inner wall of the front hood / inner panel 11 provided below the front hood / outer panel 14 of the engine room 15. On the other hand, on the lower surface of the film 2 on the lower side, the sound absorbing effect is improved, and further, the vehicle sound wave absorption control device 10 is provided.
The sound wave absorber 12 having appropriate rigidity and elasticity is attached in order to protect the. The lower surface of the sound wave absorbing material 12 is covered with a known lining material 13 made of resin foam such as polyurethane, polypropylene or polystyrene covered with vinyl leather, vinyl sheet, woven cloth or the like, or a reinforcing material such as aluminum alloy or steel plate. Thus, the vehicle sound wave absorption control device 10 and the sound wave absorption material 12 are invisible from the outside.

The films 1 and 2 are electrode plates 3 and
It is possible to improve the sealing performance of the vehicle sound wave absorption control device 10 so that the electrode plates 3 and 4 are not damaged by the direct contact of the other member such as the inner panel 11 or the sound wave absorbing member 12 with the member 4. Optional, specifically PE
T (polyethylene terephthalate) film, PVC
Various plastic films such as (vinyl chloride) film, nylon film, polyethylene film, polypropylene film, and acrylic film are used. The sound wave absorbing material 12 is arbitrary as long as it has a large number of holes and has an appropriate rigidity such as a honeycomb material and an expanded metal, and the material is not limited. The above-described films 1, 2, the sound wave absorbing material 12, and the lining material 13 have high temperatures (about 1
Since the temperature is around 20 ° C.), it is particularly preferable to use a material having excellent heat resistance.

As shown in FIG. 5, the ENC fluid composition 40 comprises EA particles 31, which are solid particles, uniformly dispersed in an electrically insulating medium 30. The EA particles 31 include a core body 32 made of an organic polymer compound and an EA
The inorganic-organic composite particles 36 are formed by the surface layer 35 including the particles 34 which are the inorganic substances 33. In this example, the electrically insulating medium 30 is colorless and transparent silicone oil, and the core 32 of the inorganic-organic composite particles 36 is used.
The organic polymer compound forming the is a polyacrylic acid ester, and the particles 34 of the EA inorganic substance 33 forming the surface layer 35.
Is white titanium hydroxide that is both an inorganic ion exchanger and an electrically semiconductive inorganic material. The color of the EA particles 31 (inorganic / organic composite particles 36) is, for example, white. The proportion of EA particles 31 contained in the electrically insulating medium 30 is, for example, 7.5% by weight.

The electrically insulating medium 30 used in the ENC fluid composition 40 of the present invention is, for example, diphenyl chloride,
Butyl sebacate, aromatic polycarboxylic acid higher alcohol ester, halophenyl alkyl ether, trans oil, chlorinated paraffin, fluorine oil, silicone oil, fluorosilicone oil, etc. Chemically stable and E
Any fluid or a mixture thereof can be used as long as it can stably disperse the A particles 31. The electrically insulating medium 30 can be colored according to the purpose. In the case of 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 30 and does not impair its electrical characteristics. In addition to this, the electrically insulating medium 30 includes a dispersant, a surfactant,
Viscosity modifiers, antioxidants, stabilizers and the like may be included.

The kinematic viscosity of this electrically insulating medium 30 is 1c.
It is preferably in the range of St to 30,000 cSt. If the kinematic viscosity is less than 1 cSt, the storage stability of the fluid composition will be insufficient, and the kinematic viscosity will be 30,000 cSt.
If it is larger, it is difficult to uniformly disperse the EA particles 31, and bubbles are entangled during the adjustment, which makes it difficult for the bubbles to escape, which is unfavorable in handling. 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 30 changes with temperature, and this temperature effect can be suppressed by the applied voltage.

The EA particles 31 used in the present invention are EA particles.
If the inorganic-organic composite particles 36 have the effect, the element,
Any material such as an organic compound, an inorganic compound, or a mixture thereof can be used. Examples thereof include particles of inorganic ion exchangers, metal oxides, silica gel, electric semiconductor inorganics, carbon black and the like, and particles having these as the surface layer 35. However, as shown in the above-mentioned examples, the EA particles 31 have a core body 32 made of an organic polymer compound and an EA particle.
It is particularly preferable that the inorganic-organic composite particles 36 are formed by the surface layer 35 including the particles 34 of the inorganic material 33. This inorganic / organic composite particle has a relatively high specific gravity of EA.
A surface layer 35 composed of particles 34 of an inorganic substance 33 is carried on a core body 32 which is an organic polymer compound having a relatively low specific gravity, and the specific gravity of the entire particles can be adjusted so as to approximate to the electrically insulating medium 30. . Therefore, the ENC fluid composition 40 obtained by dispersing this in the electrically insulating medium 30 has excellent storage stability.

EA particles 31 (inorganic / organic composite particles 36)
Examples of the organic polymer compound that can be used as the core body 32 of Poly (meth) acrylic acid ester, (meth) acrylic acid ester-styrene copolymer, polystyrene, polyethylene, polypropylene, nitrile rubber, butyl rubber, ABS resin , Nylon, polyvinyl butyrate, ionomer, ethylene-vinyl acetate copolymer, vinyl acetate resin, polycarbonate resin and the like, or a mixture or copolymer of two or more thereof.

Various particles can be used as the particles 34 which are the EA inorganic substance 33 forming the surface layer 35, and preferred examples include an inorganic ion exchanger, silica gel and an electrically semiconductive inorganic substance. Using these particles 34, a surface layer 35 is formed on the core body 32 made of an organic polymer compound.
The resulting inorganic / organic composite particles 36 become useful EA particles 31 when forming

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 MO _x (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 hydroxide. zirconium,
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. M _b-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 existing 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 exchanger 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 700
Heat treatment at ℃) etc. These inorganic ion exchangers are not only one kind, but many kinds at the same time.
It can also be used as 5. 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.

The EA particles 31 (inorganic / organic composite particles 3
An example of the electrically semiconductive inorganic material that can be used as the surface layer 35 of 6) is that the electrical conductivity is 10 ³ to 10 ^-11 Ω ^-1 / c at room temperature.
m metal oxide, metal hydroxide, metal oxide hydroxide, inorganic ion exchanger, or at least one of these
The seeds may be metal-doped, or at least one of them may be applied as an electric semiconductor layer on another support regardless of the presence or absence of metal doping.

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 (O
H) ₄ ) is 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 EA inorganic substance: This is obtained by doping the ER inorganic substance with a metal such as antimony (Sb) in order to increase the electrical conductivity of the above-mentioned electric semiconductor inorganic substances (A) to (L). For example, antimony (S
b) Doping 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 in this manner can be regarded as the EA inorganic substance 33 as a whole. These EA inorganic substances may be used not only in one kind but also in two kinds or more simultaneously as a surface layer.

EA particles 31 (inorganic / organic composite particles 36)
Can be produced by various methods. For example, there is a method in which a particulate core body 32 made of an organic polymer compound and fine particulate particles 34 are transported by a jet stream and collided with each other to produce them. In this case, the particulate core 3
The fine particles of the particles 34 collide with the surface of 2 at a high speed and are fixed to form the surface layer 35. Another example of the manufacturing method is a method in which the particulate core body 32 is suspended in a gas, and a solution of the particles 34 is atomized and sprayed on the surface. In this case, the surface layer 35 is formed by the solution adhering to the surface of the core 32 and drying.

EA particles 31 (inorganic / organic composite particles 36)
A particularly preferable manufacturing method for manufacturing is the method of forming the surface layer 35 at the same time as the core body 32. This method is, for example, when emulsion-polymerizing, suspension-polymerizing, or dispersion-polymerizing a monomer of the organic polymer compound forming the core 32 in a polymerization medium,
Particles 34, which are finely divided EA inorganic substances 33, are present in the above-mentioned monomer or 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 monomer is polymerized in the polymerization medium to form the core body 32, and at the same time, the particles 34 of the fine particle EA inorganic substance 33 form the core body 3.
A surface layer 35 is formed by orienting it in a layered manner on the surface of No. 2 and covering it.

When the EA particles 31 (inorganic / organic composite particles 36) are produced by emulsion polymerization or suspension polymerization,
By combining the hydrophobic property of the monomer and the hydrophilic property of the EA inorganic substance 33, most of the particles 34 of the EA inorganic substance 33 can be attached to the surface of the core body 32. According to the method for simultaneously forming the core body 32 and the surface layer 35, the particles 34 of the EA inorganic substance 33 are densely and firmly adhered to the surface of the core body 32 made of an organic polymer compound, and the robust E
A particles 31 (inorganic / organic composite particles 36) are formed.

The shape of the EA particles 31 used in the present invention does not necessarily need to be spherical, but the particle-shaped core body 32 is used.
When the EA particles 31 are produced by a controlled emulsion / suspension polymerization method, the resulting EA particles 31 have a substantially spherical shape.
Although the particle size of the EA particles 31 is not particularly limited,
0.1 μm to 500 μm, especially 5 μm to 200
It is preferably within the range of μm. At this time, the particle size of the particles 34, which are the fine particle EA inorganic substance 33, is not particularly limited, but preferably 0.005 μm to 1
00 μm, more preferably 0.01 μm to 10 μm
Within the range of m.

EA particles 31 (inorganic / organic composite particles 36)
In the above, the weight ratio of the particles 34, which are the EA inorganic substance 33 forming the surface layer 35, to the organic polymer compound forming the core 32 is not particularly limited, but E with high storage stability is used.
In order to obtain the NC fluid composition 40, the particles 34 are in the range of 1% by weight to 60% by weight, particularly 4% by weight, based on the total weight of the particles 34 of the EA inorganic substance 33 and the core 32 of the organic polymer compound. It is preferably in the range of 30 to 30% by weight. If the proportion of the core 32 is less than 1% by weight, the EA characteristics of the obtained EA particles 31 will be insufficient, and 60% by weight will be obtained.
If it exceeds, the specific gravity of the EA particles 31 may become excessive and the storage stability may be impaired. Further, the ENC fluid composition 40 of the present invention contains the above-mentioned EA particles 31 and, if necessary, a dispersant,
It can be manufactured by uniformly stirring and mixing it in the electrically insulating medium 30 together with other components. As the stirrer, any stirrer normally used for dispersing solid particles in a liquid dispersion medium can be used. The content of the EA particles 31 in the electrically insulating medium 30 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%, E is sufficient.
The A effect cannot be obtained, and at 75% or more, the initial viscosity of the ENC fluid composition 40 when a voltage is not applied becomes excessively large, which makes it difficult to use.

Various methods described above, particularly the core 32 and the surface layer 35.
EA particles produced by a method of simultaneously forming and
In No. 1, the whole or a part of the surface layer 35 is covered with a thin film of an organic polymer substance, a dispersant used in the manufacturing process, an emulsifier and other additive substances, and E as the EA particles 31
The A effect may not be fully exerted. This thin film of inert material can be easily removed by polishing the surface of the particles. Therefore, when the core body 32 and the surface layer 35 are simultaneously formed, it is preferable to polish the surfaces thereof.

The surface of the particles can be polished by various methods. For example, the EA particles 31 which are the inorganic / organic composite particles 36 may be dispersed in a dispersion medium such as water and the mixture may be stirred. At this time, a method of mixing abrasives such as sand particles or balls into the dispersion medium and stirring with EA particles 31, a method of stirring with a grinding wheel, or the like can also be used. For example, it is also possible to carry out dry stirring without using a dispersion medium, using the EA particles 31 and the above-mentioned abrasive or grinding stone.

A more preferable polishing method is EA particles 31.
Is a method of stirring the air flow by a jet air flow 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 31, etc., but generally 0.5 min to 15 min at a stirring speed of 6000 rpm.
It is preferable to stir with a jet stream.

The ENC fluid composition 40 of the present invention can be produced by uniformly stirring and mixing the above-mentioned EA particles 31 in the electrically insulating medium 30 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.

Next, the operation of the vehicle sound wave absorption control apparatus 10 having the above-described configuration and the vehicle sound wave absorption control method will be described. As shown in FIG. 6, when no voltage is applied between the pair of electrode plates 3 and 4, the EA particles 31 of the ENC fluid composition 40 are randomly suspended and dispersed in the electrically insulating medium 30. . Then, when a voltage is applied to the pair of electrode plates 3 and 4, as shown in FIG.
The EA particles 31 therein are arrayed and linked in a chain to form a chain (particle chain) 41, and the chain 41 is arrayed in parallel to the electric field direction.

In this state, as shown in FIG. 1, when a sound wave (air vibration) 42 is made incident on one of the electrode plates 4, one of (a), (b), (c) and (d) of FIG. The states sequentially occur, and the electrode plate 4 vibrates in the opposite direction together with the film 2 as shown by the arrow X in FIG.
Since the elastic body itself has an elastic property, as shown in FIG. 8B, when compressed, the chain-like body 41 bends in, for example, a V-shape to generate a repulsive force, As shown in (d) of FIG. 8, when the chain-like body 41 is pulled, the EA particles 31 facing each other attract each other to generate an attractive force. As a result, the movement of the chain-like body 41 in the ENC fluid composition 40 causes viscous resistance, resulting in loss (dissipation) of the energy of the sound wave 42.

The tension and compression of the chain 41 are repeated with the vibration of the electrode plate 4,
As a result, the chain 41 itself also vibrates. That is, the ENC fluid composition 40 containing the chain-like body 41 and the electrode plate structure composed of the electrode plate 4 and the film 2 resonate with the sound wave 42 incident on the electrode plate 41. The sound wave frequency that gives vibration to the chain 41 is as follows.
When a sound wave 42 having a frequency matching the characteristic frequency is incident on the electrode plate 4,
The chain 41 resonates in the directions of the arrows A and B in the middle to absorb the sound wave 42 thereof, and the sound wave 43 of another frequency is reflected.

The force acting between the EA particles 31 (stress generated in the chain 41) increases as the voltage applied to the pair of electrode plates 3 and 4 increases. Therefore, the elasticity of the chain 41 itself. The modulus and viscosity increase with increasing applied voltage. The present invention utilizes this fact to remove a desired component of the sound wave 42. That is, by adjusting the applied voltage, the characteristic frequency of the particle chain 41 itself is made to coincide with the frequency of the component (sound wave having a specific wavelength) to be removed in the sound wave 42 (air vibration) incident on the electrode plate 4. As shown in FIG. 9, the chain 41 is resonated by the action of inertial force as indicated by the left and right arrows A and B, and the energy of the component of the incident sound wave to be removed is consumed, and the other sound wave component ( (Indicated by reference numeral 43) 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 vehicle acoustic wave absorption control device 10 is determined by the size of the EA particles 31, the elastic force acting between the EA particles 31, the natural frequency of the electrode plates 3 and 4, and the electrode plates 3 and 4.
It will change depending on the distance between them. In the present invention, the spherical EA particles 31 having a substantially uniform particle size are dispersed in the electrically insulating medium 30 (without using the irregular particles), so that the above-mentioned repulsive force and attractive force are maintained under a constant voltage. Does not fluctuate, and moreover, the balance between the elastic force acting between the EA particles 31 and the inertial force of the electrode plates 3 and 4 does not fluctuate easily. In the above embodiment, the chain 41 is supposed to be bent in a V shape, but in addition to this, for example, an S shape as shown in FIG. It is considered that there is a case in which it is bent into a W shape as shown in b).

In the above embodiment, the EA particles 31 (inorganic / organic composite particles 36) are removed by applying voltage.
The phenomenon of forming the chain bodies 41 in rows and arranging them in parallel has been described. However, when the number of EA particles 31 increases beyond several wt%, the chain bodies 41 are not formed in one row, but the chain bodies 41 are A plurality of columns are joined to each other to form and arrange the columns 44 as shown in FIG. In this column 44, the EA particles 31 of the left and right chain-like bodies 41 are staggered by one and adjoin each other. Regarding this, the present inventors have shown in FIG.
(B), it is more energy-stable to arrange the EA particles 31 that are dielectrically polarized in the + pole portion and the − pole portion alternately adjacent to each other and attract the + pole portion and the − pole portion. It is presumed to be because.

In the vehicle sound wave absorption control apparatus 10 of this example, the vehicle sound wave absorption control apparatus 10 is provided in the ceiling portion of the engine room, and the ENC fluid composition 40 is used.
And a desired voltage is applied between the pair of electrode plates 3 and 4 and the pair of electrode plates 3 and 4 which are provided to face each other with a gap and accommodate the ENC fluid composition 40 in the gap. The EA particles 31 are arrayed and coupled by the voltage applied between the electrode plates 3 and 4 to form a chain 41, and the stress generated in the chain 41 is The characteristic frequency of the ENC fluid composition 40 is set in accordance with the frequency of the component of the sound wave to be absorbed by adjusting the applied voltage value because the voltage can be varied depending on the magnitude of the applied voltage. be able to. Therefore,
The sound wave 42 of various frequencies can be absorbed without changing the ENC fluid composition 40. As a result, the vehicle sound wave absorption control apparatus 10 using the ENC fluid composition 40 at low cost and easy to handle. Can be provided. In particular, EA particles 31
Is composed of an inorganic / organic composite particle 36 formed by a core body 32 made of an organic polymer compound and a surface layer 35 made of an EA inorganic substance 33, a practical ENC fluid composition 40 having high storage stability. As a result, the reliability of the vehicle sound wave absorption control device 10 is further improved.

Next, a second example of the present invention will be described. The vehicle sound wave absorption control apparatus of this example is different from the vehicle sound wave absorption control apparatus 10 of the first example, as shown in FIG. 12, not the inner wall of the front hood inner panel 11, but the front hood inner panel. 11 outer walls, ie
This is a point provided between the front hood / inner panel 11 and the front hood / outer panel 14.

In the vehicle sound wave absorption control apparatus 10 of this example, since it is sandwiched between the outer panel 14 and the inner panel 11 and is already protected by the panels 11 and 14, the honeycomb plate It is also possible to omit the use of the sound wave absorbing material 12 such as the above and the lining material 13, the reinforcing material and the like shown in the first example.

Next, a third example of the present invention will be described. 13 and 14, the ENC fluid composition 40 is impregnated into the porous body 50, and the vehicle sound wave absorption control apparatus 10 of this example is different from the previous example.
Is stored between the electrode plates 3 and 4. Examples of the porous body 50 include foam resins such as sponge, expanded polystyrene, expanded polyethylene, and expanded polypropylene. In addition to these, examples of the polymer material for forming the porous body 50 include urethane, butadiene rubber, natural rubber, natural rubber + butadiene rubber, vinyl chloride, polybutadiene, acrylonitrile, and utadiene rubber. The porous body 50 may be made by adding an appropriate foaming agent. The type of the porous body 50 is not particularly limited as long as it has an appropriate elastic force and can be impregnated with the ENC fluid composition 40.

When a voltage is applied, the EA particles 31
Are arranged inside the pores of the porous body 50, so that the EA particles 3
It is preferable to adjust the type and amount of the foaming agent to be added to adjust the size of the pores in the porous body 50, the foaming ratio, and the like so that the arrangement No. 1 smoothly proceeds.

Next, the vehicle sound wave absorption control apparatus 1 of this example.
The zero operation and the vehicle sound wave absorption control method will be described. As shown in FIG. 13, in a state where no voltage is applied to the pair of electrode plates 3 and 4, the EA particles 31 in the ENC fluid composition 40 are randomly floated and dispersed inside the pores of the porous body 50. ing. Then, when a voltage is applied to those in this state, as shown in FIG. 14, they are arranged inside the pores existing in the porous body 50 to form the chain-like bodies 41. The chain-like bodies 41 have different lengths depending on the size of the holes formed, but since the voltage applied to each chain-like body 41 is the same, the stress generated in the chain-like bodies 41, That is, the attractive forces of the EA particles 31 are the same.

Therefore, the vehicle sound wave absorption control apparatus 10 of this example can also absorb the sound wave of the desired frequency by the applied voltage, and the same effect as the vehicle sound wave absorption control apparatus 10 of the previous example can be obtained. To be Furthermore, ENC
Since the fluid composition 40 is impregnated in the porous body 50,
The vibration characteristics are better than when the ENC fluid composition 40 is used as a fluid.

Further, the vehicle sound wave absorption control apparatus 1 of the present invention.
0 is not limited to the above example. For example, the vehicle sound wave absorption control device 10 is not limited to the front panel, and can be attached to panels and parts that are arranged in the vicinity of the engine and that constitute the engine room, such as a dash panel and a front frame. The site is not limited. Of course, the mounting method is also arbitrary. Further, when the frequency of the engine sound that is most frequently generated is predicted in the engine design and manufacturing stages, a fixed power supply with a constant voltage that can be applied may be used as the power supply to be used. In this case, if the fixed power supply is interlocked with the ignition switch, the ignition switch is turned on and the engine starts to start, and at the same time, the optimum voltage is applied to the electrode plates 3 and 4, so that the noise in the vehicle is automatically generated. Can be removed. Of course, the switch for operating the ON / OFF of the voltage application may be separately provided without interlocking with the ignition switch.

The means for adjusting the applied voltage value is not limited to the above example, but may be arbitrary. Then, the films 1 and 2, the sound wave absorbing material 12, and the lining material 1
3. The reinforcing material can be made of any material depending on the mounting position of the vehicle acoustic wave absorption control device and the material of the members forming the surroundings, and the use thereof can be omitted. Further, a microphone is provided in the engine room, the frequency of the sound waves collected by the microphone is recognized, and the voltage application means is controlled so that an applied voltage matching the frequency is applied to the pair of electrode plates. A control unit for controlling may be provided.

Next, the vehicle of the present invention will be described. In this vehicle, the above-described vehicle sound wave absorption control device 10 is mounted in the engine room or outside each panel constituting the engine room. As the type of vehicle, it can be used for all kinds of vehicles such as private cars, trucks, and train cars. In such a vehicle, since the sound wave of a desired frequency can be absorbed by the applied voltage value, the noise in the engine room is mitigated, and as a result, the in-vehicle environment can be more comfortably maintained. .

[0061]

Since the present invention is configured as described above, it has the following effects. By adjusting the applied voltage value in order to set the characteristic frequency of the ENC fluid composition in accordance with the frequency of the component of the sound wave to be absorbed, without changing the ENC fluid composition,
Can absorb sound waves of various frequencies, and as a result, this ENC
It is possible to provide a sound wave absorption control device for a vehicle that uses a fluid composition at low cost and is easy to handle. In particular, when the EA particles are composed of inorganic / organic composite particles formed by a core body made of an organic polymer compound and a surface layer made of an EA inorganic substance, a practical ENC fluid composition having high storage stability is obtained. As a result, the reliability of the vehicle sound wave absorption control device is further improved. Further, the vehicle sound wave absorption control device of the present invention can easily implement the vehicle sound wave absorption control method of the present invention. Further, since the vehicle equipped with the vehicle sound wave absorption control device of the present invention can absorb sound waves having a desired frequency depending on the applied voltage value, the noise in the engine room is reduced, and the vehicle interior environment is made more comfortable. The effect of being able to hold it is also obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a vehicle sound wave absorption control device of the present invention including an ENC fluid composition.

FIG. 2 is a cross-sectional view showing an embodiment when the vehicle sound wave absorption control device of the present invention is attached to an inner wall of an interior panel that constitutes a ceiling portion of an engine room.

FIG. 3 is an exploded view showing an embodiment in which the vehicle sound wave absorption control device of the present invention is attached to an inner wall of an interior panel constituting a ceiling portion of an engine room.

FIG. 4 is an exploded view showing an embodiment of the vehicle sound wave absorption control apparatus of the present invention.

FIG. 5 is a schematic view showing an example of the ENC fluid composition according to the present invention.

FIG. 6 is a cross-sectional view showing an aspect of the ENC fluid composition according to the present invention when the power is turned off.

FIG. 7 is a cross-sectional view showing an aspect of the ENC fluid composition according to the present invention when the power is turned on.

FIG. 8 is a cross-sectional view showing a state where a sound wave is incident on the vehicle sound wave absorption control apparatus of the present invention and one of the electrode plates vibrates.

FIG. 9 shows a vehicle sound wave absorption control apparatus according to the present invention,
FIG. 6 is a cross-sectional view showing a state in which sound waves are incident and the chain and one electrode plate resonate.

FIG. 10 is a diagram showing another example of the bending state of the chain in the vehicle sound wave absorption control device of the present invention.

FIG. 11 is a view showing a column in which a plurality of chains are joined to each other in the vehicle sound wave absorption control device of the present invention.

FIG. 12 is an exploded view showing an embodiment of the vehicle sound wave absorption control apparatus of the present invention.

FIG. 13 is a cross-sectional view showing an aspect of the ENC fluid composition according to the present invention when the power is off.

FIG. 14 is a cross-sectional view showing an aspect of the ENC fluid composition according to the present invention when the power is turned on.

FIG. 15 is a graph showing the results of measuring the effect of electric field strength on the EA characteristics of an electric field-aligned molecular dispersion system.

FIG. 16 is a diagram showing an equivalent circuit of a vibration system.

[Explanation of symbols]

1, 2 ... Film, 3, 4 ... Electrode plate, 5 ... Sealing member,
6 ... Power source, 7 ... Switch, 10 ... Vehicle sound wave absorption control device, 11 ... Front hood / inner panel, 12 ... Sound wave absorbing material, 13 ... Lining material, 14 ... Front hood / outer panel, 30 ... Electrically insulating medium , 31 ... EA particles, 33 ... EA inorganic substances, 36 ... Inorganic / organic composite particles, 4
0 ... ENC fluid composition, 41 ... Chain body, 42, 43 ... Sound wave, 44 ... Column, 50 ... Porous body

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location G10K 11/178 11/162 G10K 11/16 A (72) Inventor Kazuya Eedura Shiba Park, Minato-ku, Tokyo 2-6-15 Fujikura Kasei Co., Ltd. Head Office (72) Inventor Hidenobu Anzai 1-15-1 Kiba, Koto-ku, Tokyo Fujikura Ltd. (72) Inventor Yasufumi Otsubo Inage-ku, Chiba City, Chiba Prefecture Konakadai 9-21-1 206

Claims (7)

[Claims] 1. A sound wave absorption control apparatus for a vehicle, which is provided in an engine room of a vehicle, wherein a solid particle having an electric field arranging effect is contained in an electrically insulating medium. An object, a pair of electrode plates that are provided to face each other with a gap, and that accommodates the fluid composition for electro-sensitive sound wave absorption control in the gap, and a desired voltage is applied between the pair of electrode plates. A sound wave absorption control device for a vehicle, comprising: 2. A sound wave absorption control device for a vehicle, which is provided outside an interior panel constituting an engine room of a vehicle, wherein solid particles having an electric field array effect are contained in an electrically insulating medium. -Type sound wave absorption control fluid composition, a pair of electrode plates provided to face each other with a gap, and containing the electrosensitive sound wave absorption control fluid composition in the gap, and the pair of electrode plates A sound wave absorption control device for a vehicle, comprising: a power supply for applying a desired voltage therebetween. 3. The porous body impregnated with the fluid composition for electro-sensitive acoustic wave absorption control is housed in a gap formed between the pair of electrode plates. Vehicle sound wave absorption control device. 4. The sound wave absorption control device for a vehicle according to claim 1, wherein the power supply is a variable power supply that varies an applied voltage. 5. A vehicle comprising the vehicle sound wave absorption control device according to any one of claims 1 to 4. 6. A fluid composition for electro-sensitive sound wave absorption control, comprising solid particles having an electric field arranging effect in an electrically insulating medium on the outside of an engine room of a vehicle or an interior panel constituting the engine room. A pair of electrode plates provided facing each other with a gap and accommodating the fluid composition for electro-sensitive sound wave absorption control in the gap, and a power supply for applying a desired voltage between the pair of electrode plates. The vehicle acoustic wave absorption control device provided is provided, while applying a voltage between the pair of electrode plates to control the arrangement of the solid particles to form a particle chain, and the characteristic frequency of the particle chain is one of A method for controlling absorption of sound waves for a vehicle, characterized in that the applied voltage is adjusted before or after applying a voltage so as to match the frequency of a component of a sound wave incident on an electrode plate to be absorbed. 7. The method for controlling sound wave absorption for a vehicle according to claim 6, wherein a porous body impregnated with a fluid composition for electro-sensitive sound wave absorption control is provided between the electrode plates.