US20070235253A1 - Sound-absorbing material, production method of the same, and sound-absorbing panel - Google Patents

Sound-absorbing material, production method of the same, and sound-absorbing panel Download PDF

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Publication number
US20070235253A1
US20070235253A1 US11/723,850 US72385007A US2007235253A1 US 20070235253 A1 US20070235253 A1 US 20070235253A1 US 72385007 A US72385007 A US 72385007A US 2007235253 A1 US2007235253 A1 US 2007235253A1
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Prior art keywords
sound
absorbing material
absorbing
pierced
forming agent
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US11/723,850
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English (en)
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Tatsuya Hiraku
Takao Nakaya
Yoshihiro Tada
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Yamaha Corp
University of Tokushima NUC
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Individual
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Assigned to YAMAHA CORPORATION, THE UNIVERSITY OF TOKUSHIMA reassignment YAMAHA CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TADA, YOSHIHIRO, HIRAKU, TATSUYA, NAKAYA, TAKAO
Publication of US20070235253A1 publication Critical patent/US20070235253A1/en
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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/172—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using resonance effects

Definitions

  • the present invention relates to a sound-absorbing material, a production method of the same and a sound-absorbing panel.
  • glass wool, rock wool, and the like As sound-absorbing materials of the prior art, porous materials such as glass wool, rock wool, and the like are well-known.
  • glass wool, rock wool and the like have problems such as: having detrimental influences on the surrounding environment due to fibers, dust/particles, and the like; decreasing sound-absorbing characteristics because of the influence of dust, humidity, chemicals, grease, and the like; and providing less freedom of beauty or less freedom in appearance because of external delustering or frosting.
  • glass wool, rock wool, and the like are not generally used alone, and it is necessary to use them together with other materials such as clothes, nets, and the like having high permeability in order to improve their external appearance or to obtain durability; therefore, there is a problem in which beauty or the appearance is limited.
  • a sound-absorbing panel in which pierced apertures are provided on a plate member made from metal, wood, plastic, and the like, and in which a backside air layer is provided on an opposite side against a sound source, is well-known.
  • a diameter of the pierced aperture is comparatively large and can be seen by the naked eye; therefore, there is a problem in which beauty or the appearance is lessened.
  • similar to glass wool, rock wool, and the like it is necessary to use them together with other materials such as clothes, nets, and the like having high permeability, therefore, there is a problem in which beauty or the appearance is limited.
  • a sound-absorbing panel which has pierced apertures of a few hundred micrometers in diameter is well-known (for example, Japanese Patent Application, First Publication No. 2005-173398); however, the pierced apertures of this sound-absorbing panel are provided by perforating with a drill, by applying a lithography technique, and the like; therefore, there is a problem in which production cost is high. Moreover, there is a problem in which the thicker the panel is, the larger the aspect ratio of the pierced aperture is; therefore, it is difficult to produce the sound-absorbing panel that has large thickness.
  • the present invention was devised in order to achieve an object of providing a sound-absorbing material which has excellent characteristics of beauty or the appearance and of sound-absorbing, a production method of the same and a sound-absorbing panel including the sound-absorbing material.
  • a sound-absorbing material of the present invention is characterized by comprising: a plate-shaped member made from a metal; and a plurality of pierced apertures of 200 ⁇ m or smaller diameter provided on the plate-shaped member, and arranged along a board thickness direction of the plate-shaped member.
  • a sound-absorbing material production method of the present invention is characterized by comprising the steps of: mixing a metallic powder and a pierced aperture forming agent powder; forming a bulk body by solidifying and forming both the metallic powder and the pierced aperture forming agent powder along with drawing or drafting in a direction in a fibrous state; forming a plate-shaped member by slicing the bulk body along an orthogonal direction to a drawn or drafted direction; and forming a plurality of pierced apertures of a 200 ⁇ m or smaller in diameter by removing the pierced aperture forming agent from the plate-shaped member.
  • a sound-absorbing material of the present invention is made by applying the above-described sound-absorbing material production method.
  • an aperture ratio of the pierced apertures may preferably be in a range of 10-80%.
  • a mixture of both the metallic powder and the pierced aperture forming agent powder may preferably be extruded by applying a hot extrusion method upon forming the bulk body.
  • This hot extrusion method may preferably be conducted by applying a temperature at which the metallic powder and the pierced aperture forming agent powder are melted, or lower.
  • the metallic powder may preferably be one of Al, Mg, Sn or Cu, an alloy made from one of these metals as a main raw material, or a mixed powder of one of these metallic powders and the alloy, and it may especially preferably be Al.
  • the pierced aperture forming agent may preferably be made from a water-soluble salt, and NaCl may especially be preferable.
  • a sound-absorbing panel of the present invention may be characterized by comprising: two or more above-described sound-absorbing materials arranged at relatively sliding positions with a predetermined interval therebetween; and one or more air layers arranged between the sound-absorbing materials.
  • a sound-absorbing panel of the present invention may be characterized by comprising: a sound-absorbing material described above; a rigid body arranged at a relatively sliding position from the sound-absorbing material with a predetermined interval therebetween; and an air layer arranged between the sound-absorbing material and the rigid body.
  • a sound-absorbing panel of the present invention described above may preferably further comprise a porous sound-absorbing material arranged at the air layer.
  • a porous sound-absorbing material for example, it is possible to apply a glass wool, a rock wool, and the like.
  • a sound-absorbing panel of the present invention described above may preferably further comprise a reinforcing member attached to a side of the air layer of the sound-absorbing material.
  • multiple pierced apertures which are 200 ⁇ m or smaller and which are directed along the thickness direction of the board member; therefore, it is possible to improve the sound-absorbing characteristic.
  • the diameter of the pierced aperture is 200 ⁇ m or shorter; therefore, the pierced aperture is not conspicuous and does not give unpleasant effects on beauty.
  • a bulk object is formed by solidifying and shaping both the metallic powder and the pierced aperture forming agent powder along with being extended toward one direction in a fiber state, and the pierced aperture is formed by removing the pierced aperture forming agent powder after this bulk object is sliced in a board state along a perpendicular direction to the extending direction; therefore, there is less opportunity in which one end or both ends of the pierced aperture are blocked or closed. Therefore, it is possible to constitute the sound-absorbing material which provides the pierced apertures which have a large aspect ratio and which extend along a direction of the board thickness. Such the sound-absorbing material has an excellent sound-absorbing characteristic.
  • the aperture ratio or the opening ratio is set to be in a range from 10% to 80%; therefore, it is possible to ward off unstableness upon producing or reducing strength as a panel.
  • a bulk object is formed by solidifying and shaping both the metallic powder and the pierced aperture forming agent powder along with drawing or drafting toward one direction in a fiber state, and the pierced aperture is formed by removing the pierced aperture forming agent after this bulk object is sliced in a board state along a perpendicular direction to the drawn or drafted direction; therefore, there is less opportunity in which one end or both ends of the pierced aperture are blocked or closed, and it is possible to produce the low-cost sound-absorbing material that provides the pierced apertures which extend along a direction of the board thickness and which have a large aspect ratio. Moreover, it is possible to apply larger board thickness (length of the pierced aperture) to the sound-absorbing material. Such the sound-absorbing material has an excellent sound-absorbing characteristic.
  • a pair of the sound-absorbing materials or a sound-absorbing material and a rigid body are arranged so as to face each other, and an air layer is provided between a pair of the sound-absorbing materials or between the sound-absorbing material and the rigid body; therefore, it is possible to constitute a so-called Helmholtz resonator from the pierced apertures of the sound-absorbing material and the air layer, and it is possible to significantly increase the sound-absorbing characteristic.
  • the sound-absorbing material itself has an excellent beauty; therefore, it is possible to increase beauty of the sound-absorbing panel itself.
  • a porous sound-absorbing material is arranged therein; therefore, it is possible to further improve the sound-absorbing characteristic.
  • a reinforcing member is attached to a side of the air layer of the sound-absorbing material; therefore, it is possible to improve strength of the sound-absorbing material itself and to achieve a larger panel surface of the sound-absorbing panel.
  • FIG. 1 is an oblique perspective view of a sound-absorbing material of an embodiment of the present invention.
  • FIG. 2 is a partial cross-sectional schematic view of the sound-absorbing material shown in FIG. 1 .
  • FIG. 3 is a cross-sectional schematic view showing one example of a sound-absorbing panel of an embodiment of the present invention.
  • FIG. 4 is a cross-sectional schematic view showing another example of a sound-absorbing panel of an embodiment of the present invention.
  • FIG. 5 is a cross-sectional schematic view showing another example of a sound-absorbing panel of an embodiment of the present invention.
  • FIG. 6 is a cross-sectional schematic view showing another example of a sound-absorbing panel of an embodiment of the present invention.
  • FIG. 7 is a flowchart for explaining a production method of the sound-absorbing material of the embodiment of the present invention.
  • FIGS. 8A-8C are schematic views for explaining one step of a production method of the sound-absorbing material of the embodiment of the present invention.
  • FIG. 9 is a waveform chart showing a sound-absorbing characteristic of the sound-absorbing panel of the first embodiment of the present invention, and is a graph showing a frequency-dependent characteristic of a sound-absorption coefficient.
  • FIG. 10 is a waveform chart showing a sound-absorbing characteristic of the sound-absorbing panel of the first embodiment of the present invention, and is a graph showing a frequency-dependent characteristic of a sound-absorption coefficient in a case in which glass wool is filled in a backside air layer.
  • FIG. 1 is an oblique perspective view of the sound-absorbing material of this embodiment
  • FIG. 2 is a cross-sectional schematic view of a portion of the magnified sound absorbing material shown in FIG. 1 .
  • a sound-absorbing material 1 of this embodiment is constituted from a plate-shaped member 2 which is made from a metal, and is produced in accordance with a production method explained below.
  • This plate-shaped member 2 has a surface 2 a and another surface 2 b which have the largest area of all surfaces that are external surfaces of the plate-shaped member.
  • the surface 2 a and the surface 2 b are facing each other along with being arranged along a thickness direction of the plate-shaped member 2 .
  • On these surfaces 2 a and 2 b as shown in FIG. 2 , multiple pierced apertures 3 are provided.
  • an area on the surfaces 2 a and 2 b on which the pierced apertures 3 are not provided is a metal surface 2 c.
  • the plate-shaped member 2 is made from a metal, to be one of Al, Mg, Sn or Cu, or an alloy mainly made from one of these metals, or to be a mixed object of both these metals and the alloy, and Al is especially preferable.
  • a thickness t of the plate-shaped member 2 is preferably in a range from 0.5 mm to 10 mm, and a range from 1 mm to 5 mm is further preferable. It should be noted that the thickness t of the plate-shaped member 2 corresponds to a length of the pierced aperture along the board thickness direction. If the thickness t of the plate-shaped member 2 (length of the pierced aperture) is 0.5 mm or larger, it is preferable because there is no possibility of the strength of the plate-shaped member 2 decreasing and the sound-absorbing characteristic dropping. Moreover, if the thickness t of the plate-shaped member 2 (length of the pierced aperture) is 10 mm or less, there is no possibility of one or both ends of the pierced aperture 3 being closed or blocked and the sound-absorbing characteristic dropping.
  • the pierced aperture 3 exists along with extending along the board thickness direction of the plate-shaped member 2 , and pierces through the plate-shaped member 2 .
  • a shape of the pierced aperture 3 seen on a surface a circular shape is preferable; however, an oval shape, a rectangular shape or a polygon with rounder angles is possible.
  • a diameter d of the pierced aperture 3 (a diameter of an equivalent circle corresponding to an area of a cross-section of the aperture) can be in a range of 200 ⁇ m or less, preferably the range is from 10 ⁇ m to 200 ⁇ m, and more preferably, the range is from 50 ⁇ m to 200 ⁇ m. If the diameter d is smaller than 50 ⁇ m, it is difficult to remove the pierced aperture forming agent. Moreover it is possible that the diameters d of the pierced apertures 3 be respectively different.
  • the diameter d is larger than 200 ⁇ m, it is easy to see the pierced aperture 3 by the naked eye and beauty or the appearance of the sound-absorbing material 1 is decreased; therefore, it is not preferable.
  • the shape of the pierced aperture 3 seen on the surface and its size be constant along the thickness direction of the plate-shaped member 2 ; however, it is possible that the size be gradually changed along the thickness direction of the plate-shaped member 2 .
  • the shape seen on the surface and its size are respectively constant along the thickness direction of the plate-shaped member 2 , and there is a relationship in which the wall surface 3 a of the pierced aperture 3 is crossing the surfaces 2 a and 2 b at a right angle; however, it is possible that the wall surface of the pierced aperture 3 be a tapered surface.
  • an aperture ratio s of the pierced apertures 3 be set to be in a range from 10% to 80%, and the range is preferably from 20% to 60%.
  • the aperture ratio s of the pierced apertures 3 is a ratio of the opening area of the pierced apertures 3 to the area of the surface 2 a or the surface 2 b. If the aperture ratio s is 10% or more, there is no possibility of decreasing the sound-absorbing characteristics caused by a lack of the pierced apertures 3 , and it is easy to remove the pierced aperture forming agent in a production step described later. Moreover, if the aperture ratio s is 80% or less, there is no possibility of connecting the pierced apertures 3 to each other, and it is possible to obtain sufficient strength of the sound-absorbing material 1 .
  • the above-described sound-absorbing material 1 be arranged so as to set the surface 2 a or 2 b to face a position of a sound source.
  • the surface which is on an opposite side of the sound-absorbing material 1 against the position of the sound source is exposed to an air layer, and this air layer and the pierced apertures 3 of the sound-absorbing material 1 are connected so as to form a so-called Helmholtz resonator; therefore, it is possible to obtain a sound-absorbing ability.
  • a sound-absorbing ability of the Helmholtz resonator is determined in accordance with the thickness t of the plate-shaped member 2 (length of the pierced aperture), the diameter d of the pierced aperture 3 , intervals, gaps or distances among the pierced apertures 3 , and the like; therefore, it is possible to determine appropriate settings within the above-described most preferable ranges in order to obtain the maximum sound-absorbing ability in accordance with acoustic characteristics such as frequency of the sound aimed to be absorbed.
  • the thickness t of the plate-shaped member 2 (length of the pierced aperture), the diameter d of the pierced aperture 3 and the aperture ratio s of the pierced apertures 3 so as to enlarge a maximum sound-absorbing ratio a 0 , which is explained in a document (Dah-You Maa,“Potential of microperforated panel absorber”, J.Acoust.Soc.Am., Vol. 104, No. 5, November, 1998).
  • r in a formula (1) is calculated in accordance with a formula (2)
  • k r in the formula (2) is calculated in accordance with a formula (3)
  • k in the formula (3) is calculated in accordance with a formula (4).
  • t is a thickness of the plate-shaped member 2
  • d is a diameter of the pierced aperture 3
  • s is an aperture ratio of the pierced aperture 3
  • ⁇ is a viscosity of air
  • ⁇ 0 is a density of the air
  • c is a speed of sound in the air
  • ⁇ is an angular frequency.
  • multiple pierced apertures 3 are provided which are 200 ⁇ m or smaller and which are directed along the thickness direction of the board member 2 ; therefore, it is possible to improve the sound-absorbing characteristics.
  • the diameter of the pierced aperture is 200 ⁇ m or smaller; therefore, the pierced apertures 3 are not conspicuous and do not adversely affect beauty or the appearance.
  • the aperture ratio of the pierced apertures 3 is in a range from 10% to 80%; therefore, it is possible to achieve excellent sound absorbing characteristics.
  • FIG. 3-6 a sound-absorbing panel including the above-described sound-absorbing material is explained.
  • FIG. 3 is a cross-sectional schematic view showing one example of the sound-absorbing panel of an embodiment.
  • a sound-absorbing panel 10 shown in FIG. 3 is formed from a pair of the above-described sound-absorbing materials 1 A( 1 ) and 1 B( 1 ) which are arranged so as to face each other with a predetermined interval in between.
  • an air layer 11 is provided between the sound-absorbing materials 1 A and 1 B.
  • the air layer 11 is provided between the sound-absorbing materials 1 A and 1 B, and the air layer 11 and the pierced apertures 3 of the sound-absorbing material 1 A and 1 b are connected so as to form the so-called Helmholtz resonator. Therefore, it is possible to largely improve a sound-absorbing ability.
  • a thickness of the air layer 11 is preferably in a range from 5 mm to 1000 mm, and more preferably the range is from 50 mm to 500 mm. It is not possible to obtain preferable sound-absorbing characteristics if the thickness of the air layer 11 is out of this range.
  • the sound-absorbing panel 10 shown in FIG. 3 is provided with the sound absorbing materials 1 A and 1 B, which have the same constitution; therefore, it is possible to arrange one of the sound-absorbing materials 1 A and 1 B so as to face the sound source. It is possible to freely arrange a direction of the sound-absorbing panel 10 regardless of a position of the sound source upon executing or arranging; and therefore, freedom of execution or arrangement is improved.
  • FIG. 4 is a cross-sectional schematic view showing another example of a sound-absorbing panel.
  • a sound-absorbing panel shown in FIG. 4 has a constitution in which the above-described sound-absorbing material 1 A and a rigid body 21 in a plate shape are facing each other so as to have a predetermined interval.
  • an air layer 22 is provided between the sound-absorbing material 1 A and the rigid body 21 .
  • the air layer 22 is provided between the sound-absorbing materials 1 A and the rigid body 21 , and the air layer 11 and the pierced apertures 3 of the sound-absorbing material 1 A are connected so as to form the so-called Helmholtz resonator. Therefore, it is possible to greatly improve a sound-absorbing ability.
  • a thickness of the air layer 22 is preferably in a range from 5 mm to 1000 mm, and more preferably the range is from 50 mm to 500 mm. It is not possible to obtain preferable sound-absorbing characteristics if the thickness of the air layer 22 is out of this range.
  • the sound-absorbing material 1 A it is preferable to arrange the sound-absorbing material 1 A so as to face the sound source. Therefore, the sound waves efficiently enter the pierced apertures 3 of the sound-absorbing material 1 A, and it is possible to obtain excellent sound-absorbing characteristic.
  • FIG. 5 is a cross-sectional schematic view which shows another example of a sound-absorbing panel.
  • a sound-absorbing panel 30 shown in FIG. 5 has a constitution in which the above-described sound-absorbing material 1 A and the rigid body 21 in a plate shape are facing each other so as to have a predetermined interval, and moreover, the constitution includes a porous sound-absorbing material 31 which is arranged between the sound-absorbing material 1 A and the rigid body 21 (an air layer 22 ). As in FIGS. 3 and 4 , by arranging the sound-absorbing material 1 A and the rigid body 21 so as to have an interval, the air layer 22 is provided between the sound-absorbing material 1 A and the rigid body 21 .
  • the air layer 22 is provided between the sound-absorbing material 1 A and the rigid body 21 , and the air layer 11 and the pierced apertures 3 of the sound-absorbing material 1 A are connected so as to form the so-called Helmholtz resonator. Therefore, it is possible to greatly improve a sound-absorbing ability.
  • the porous sound-absorbing material 31 is arranged at the air layer 22 ; therefore, it is possible to further improve the sound-absorbing characteristics of the sound-absorbing panel 30 .
  • the porous sound-absorbing material 31 for example, it is possible to apply glass wool, rock wool and the like.
  • a thickness of the air layer 22 is preferably in a range from 5 mm to 1000 mm, and more preferably the range is from 50 mm to 500 mm. It is not possible to obtain preferable sound-absorbing characteristics if the thickness of the air layer 22 is out of this range.
  • the sound-absorbing panel 30 shown in FIG. 5 As in a case of the sound-absorbing panel 20 shown in FIG. 4 , it is preferable to arrange the sound-absorbing material 1 A so as to face the sound source. Therefore, the sound waves efficiently enter the pierced apertures 3 of the sound-absorbing material 1 A, and it is possible to obtain excellent sound-absorbing characteristics.
  • FIG. 6 is a cross-sectional schematic view which shows another example of a sound-absorbing panel.
  • a sound-absorbing panel 40 shown in FIG. 6 has a constitution in which the above-described sound-absorbing material 1 A and the rigid body 21 in a plate shape are facing each other so as to have a predetermined interval, and moreover, the constitution includes a reinforcing member 41 which is attached to a side of a surface 1 a of the sound-absorbing material 1 A (an air layer). It is possible to arrange an interval between the reinforcing member 41 and the rigid body 21 and to adhere the reinforcing member 41 and the rigid body 21 .
  • the reinforcing member 41 at a side of the surface 1 a, which is a side of the rigid body of the sound absorbing material 1 A, or to arrange at an side of the surface 1 b, which is an opposite side from the rigid body; however, from a point of view of improving beauty or the appearance of the sound-absorbing panel 40 , it is preferable to arrange at a side of the surface 1 a, which is a side of the rigid body 21 of the sound absorbing material 1 A.
  • the reinforcing member 41 it is possible to apply, for example, a member which includes intervals, gaps, vacant spaces or apertures such as: a honeycomb panel made from a metal such as aluminum; a panel in a grid or crib shape; a rib; and the like. In accordance with such a manner, there is no possibility in which the pierced aperture 3 and the air layer 22 are blocked or completely separated by the reinforcing member 41 .
  • the air layer 22 is provided between the sound-absorbing material 1 A and the rigid body 21 . It should be noted that, with respect to the sound-absorbing panel 40 shown in FIG. 6 , the gaps of the reinforcing member 41 and the air layer 22 are connected, and the gaps of the reinforcing member 41 are included as a portion of the air layer 22 .
  • the air layer 22 is provided between the sound-absorbing materials 1 A and the rigid body 21 , and the so-called Helmholtz resonator is constituted from both the pierced apertures 3 of the sound-absorbing material 1 A and the air layer 11 . Therefore, it is possible to greatly improve a sound-absorbing ability.
  • the reinforcing member 41 is attached to the sound-absorbing material 1 A; therefore, it is possible to improve the strength of the sound-absorbing material 1 A itself
  • an interval m 4 between the sound-absorbing material 1 A and the rigid body 21 in other words, a thickness of the air layer 22 is preferably in a range from 5 mm to 1000 mm, and more preferably the range is from 50 mm to 500 mm. It is not possible to obtain preferable sound-absorbing characteristics if the thickness of the air layer 22 is out of this range.
  • the sound-absorbing panel 40 shown in FIG. 6 As in cases of the sound-absorbing panels 20 and 30 shown in FIGS. 4 and 5 , it is preferable to arrange the sound-absorbing material 1 A so as to face the sound source. Therefore, the sound waves efficiently enter the pierced apertures 3 of the sound-absorbing material 1 A, and it is possible to obtain excellent sound-absorbing characteristics.
  • porous sound-absorbing material 31 it is possible to attach the porous sound-absorbing material 31 not only to the sound-absorbing panel 30 shown in FIG. 5 , but also to the sound absorbing panels 10 , 20 and 40 shown in FIGS. 3 , 4 and 6 .
  • the sound-absorbing material 1 A and the sound-absorbing material 1 B, or the sound-absorbing material 1 A and the rigid body 21 are arranged so as to face each other; the air layer 11 / 22 is provided between the sound-absorbing material 1 A and the rigid body 21 ; and the so-called Helmholtz resonator is constituted from both the pierced apertures 3 and the air layer 11 / 22 ; therefore, it is possible to greatly improve a sound-absorbing ability.
  • the sound-absorbing materials 1 A and 1 B themselves have excellent beauty or the appearance; therefore, it is possible to increase beauty or the appearance of the sound-absorbing panels 10 - 40 themselves.
  • FIG. 7 shows a flowchart of the production method of the sound-absorbing material 1 .
  • the production method of the sound-absorbing material 1 of this embodiment includes: a mixing step S 1 in which metallic powder and powder of the pierced aperture forming agent are mixed; a hot extrusion step S 2 in which a bulk body is solidified and formed along with drawing or drafting the metallic powder and the powder of the pierced aperture forming agent in one direction so as to be in a fibrous state; a slicing step S 3 in which the bulk body is sliced in a plate state in a direction perpendicular to the drawing or drafting direction; and a pierced aperture forming agent removing step S 4 in which the pierced apertures are formed by removing the pierced aperture forming agent.
  • mixed powder is manufactured by mixing both the metallic powder and the powder of the pierced aperture forming agent.
  • a mixing method it is possible to apply well-known conventional methods.
  • the metallic powder it is possible to apply one of Al, Mg, Sn or Cu, or an alloy mainly made from one of these metals, or to apply a mixed powder of these metallic powders and the alloy; however, Al is especially preferable because of a point of view such as lightness, corrosion resistance, ease of processing, cost of the material, and the like.
  • the metallic powder it is preferable to apply the metallic powder with an average particle diameter in a range of 30-1000 ⁇ m from the viewpoint that the metallic powder is processed into a fibrous state in the hot extrusion step S 2 described below. And furthermore, it is preferable to make the particle diameter of all the metallic powder to be in a range of 10-2000 ⁇ m.
  • the pierced aperture forming agent it is preferably made from water-soluble salts, NaCl or KCl is more preferable, and NaCl is especially preferable.
  • Such pierced aperture forming agents have a high melting point; and therefore, it is possible to process into the fibrous state along with avoiding reaction with the metallic powder in the hot extrusion step S 2 described below.
  • these pierced aperture forming agents are water-soluble; therefore, it is possible to easily remove them in the pierced aperture forming agent removing step explained below.
  • the pierced aperture forming agent is not limited to the above-explained materials, and it is possible to apply any material which can be drawn or drafted in one direction and be formed in a fibrous state by processing such as a hot extrusion and which can be easily removed.
  • a powder of the pierced aperture forming agent with an average particle diameter in a range of 50-1000 ⁇ m. And furthermore, it is preferable to make the particle diameter of the powder of the pierced aperture forming agent to be in a range of 30-2000 ⁇ m. If the diameter of the powder is smaller than a lower limit of this range, after extrusion, the pierced aperture forming agent becomes too narrow, in other words, the aperture diameter is too small; therefore, it is difficult to remove the pierced aperture forming agent.
  • the diameter of the powder is larger than an upper limit of this range, a larger extrusion ratio is needed in the extrusion step, and the extrusion pressure is larger; therefore, a stronger metallic mold and a larger apparatus are needed (it causes a larger cost).
  • the average particle diameters and the range of the particle diameters of the metallic powder and the powder of the pierced aperture forming agent are preferably as described above; however, they are not limited as described above, and it is possible to set them in a range in which the diameter of the pierced apertures is set to be 200 ⁇ m or smaller in accordance with a processing condition, especially a combination with the extruding ratio.
  • the mixing ratio of the metallic powder and the powder of the pierced aperture forming agent is adjusted in the above-described range; therefore, it is possible to control the aperture ratio of the sound absorbing material. If the ratio of the pierced aperture forming agent is decreased, there is a possibility in which the pierced apertures are not sufficiently formed, and in which the aperture ratio is lower.
  • the ratio of the pierced aperture forming agent is increased, there is a possibility in which the diameter of the pierced aperture is increased and it is difficult to adjust it so as to be 200 ⁇ m or smaller, and in which the aperture ratio is increased.
  • a hot extrusion operation is conducted on the above-described mixed powder, and a bulk body is solidified and formed along with drawing or drafting the metallic powder and the powder of the pierced aperture forming agent in one direction so as to be in a fibrous state.
  • a range of 3-500 as an extrusion ratio
  • Al used as the metallic powder
  • the extrusion temperature in a range from 300° C. to 600° C. If the condition is out of this range, it is difficult to form the bulk body.
  • the metallic particles of the metallic powder are associated because of the influence of pressure and temperature, and the associated metal is extruded along a drawn or drafted direction in a fibrous state.
  • the powder of the pierced aperture forming agent is integrated because of the influence of pressure and temperature, and is extruded along the extruded direction in a fibrous state or the particle itself is extruded along the drawn or drafted direction in a fibrous state.
  • Both the drawn metal in a fibrous state and the drawn pierced aperture forming agent in a fibrous state are integrated and are formed and solidified so as to be a bulk body as a whole.
  • both the drawn metal in a fibrous state and the drawn pierced aperture forming agent in a fibrous state are distributed in a mosaic state. It should be noted that the drawn direction of the fiber of the bulk body formed in the hot extrusion step is the same as the extruded direction.
  • FIG. 8 is a schematic diagram which shows the slicing step.
  • FIG. 8A is a schematic diagram of a cross-section of a bulk body 50 .
  • multiple parallel lines drawn on the cross-section of the bulk body 50 are a pierced aperture forming agent 51 drawn or drafted in a fibrous state.
  • This pierced aperture forming agent 51 is drawn or drafted in a fibrous state along the same direction as the extruded direction.
  • the bulk body 50 is sliced along a direction orthogonal to the extruded direction.
  • dashed lines are lines indicate sliced surface.
  • the pierced aperture forming agent 51 is exposed on the sliced surface, and a plate-shaped member 2 d as shown in FIG. 8C is obtained.
  • the pierced apertures are obtained by removing the pierced aperture forming agent 51 from the plate-shaped member 2 d.
  • a removing method it is possible to apply a method of eluting or volatilizing the pierced aperture forming agent.
  • the water-soluble salt is used as the pierced aperture forming agent, it is preferable to apply an elution method.
  • a sliced surface of the plate-shaped member 2 d becomes surfaces 2 a and 2 b of the plate-shaped member 2 which constitute the sound-absorbing material 1 . Therefore, there is a relationship of orthogonally crossing between the surfaces 2 a / 2 b of the sound-absorbing material 1 and the extruded direction.
  • the pierced apertures 3 are formed after conducting both the slicing step and the pierced aperture forming agent removing step, and the pierced aperture 3 is formed by removing the pierced aperture forming agent 51 ; therefore, the pierced aperture 3 extends along the same direction as the extruded direction.
  • the pierced apertures 3 provided on the sound-absorbing material 1 have a relationship of orthogonally crossing with the surfaces 2 a and 2 b. Therefore, if the surface 1 a or 1 b is arranged so as to face the sound source when the sound-absorbing material 1 is set after production, a relationship can be obtained in which the sound source is positioned on an extending direction of the pierced aperture 3 ; therefore, it is possible to mostly and effectively exert or use the sound-absorbing characteristics of the sound-absorbing material 1 .
  • the bulk object is formed by solidifying and shaping both the metallic powder and the pierced aperture forming agent powder along with extending toward one direction in a fibrous state, and the pierced apertures 3 are formed by removing the pierced aperture forming agent after this bulk object is sliced in a board state along a perpendicular direction to the extending direction; therefore, there is less chance of one end or both ends of the pierced apertures 3 being blocked or closed, and it is possible to produce the low-cost sound-absorbing material 1 that provides the pierced apertures 3 which extend along a direction of the board thickness and which have a large aspect ratio. Moreover, it is possible to enlarge the board thickness of the sound-absorbing material 1 . Such the sound-absorbing material 1 has excellent sound-absorbing characteristics.
  • the pierced apertures 3 are formed by slicing the bulk body in a plate shape along an orthogonal direction against the extruded direction; therefore, there is less chance of one end or both ends of the pierced apertures 3 being blocked or closed, and it is possible to produce the sound-absorbing material 1 that provides the pierced apertures 3 which extend along a direction of the board thickness and which have a large aspect ratio.
  • Such a sound-absorbing material 1 has excellent sound-absorbing characteristics.
  • a bulk body was formed by conducting the heat extrusion operation upon the obtained mixed powder in a condition in which an extrusion ratio was 6.9 and an extrusion temperature was 450° C.
  • the obtained bulk body was sliced in a direction orthogonally crossing against an extrusion direction, and a plate-shaped member was obtained. NaCl was soaked by soaking the plate-shaped member in water for 6 hours, and a sound-absorbing material of the first example was produced
  • Normal incidence sound absorption characteristics of the sound-absorbing material of the first example were measured by applying a transfer function method (in conformity with ISO 10534-2).
  • the sound-absorbing material of the first example was arranged at one end of a sound tube in a hollow or empty cylindrical shape of 400 mm length and 40 mm inside diameter, and a backside air layer was 150 mm.
  • a rigid body was arranged at an opposite side of the backside air layer of the sound-absorbing material.
  • a speaker was arranged at an opposite end of the sound tube.
  • two microphones were arranged between both ends of the sound tube so as to obtain a predetermined interval or gap therebetween. The speaker and the microphones were respectively connected to calculation apparatuses for measuring. In such a manner, a measuring apparatus of the normal incidence sound absorption characteristics by applying the transfer function (in conformity to ISO 10534-2) was constituted.
  • FIG. 9 shows the results. It should be noted that, in FIG. 9 , calculated values of the normal incidence sound absorption coefficient obtained by applying the above-described formula (1) are shown as well.
  • measured values correspond to calculated values very well, and it can be seen that excellent sound-absorbing characteristics were obtained.
  • the sound-absorbing material of the first comparative example is produced by piercing multiple pierced apertures of 200 ⁇ m diameter with a 200 ⁇ m pitch on an aluminum plate of 1 mm thickness by using a drill. It should be noted that the pierced apertures are arranged so as to be in a grid state.
  • the conditions are the same as the first example except for using the sound-absorbing material of the first comparative example, and the normal incidence sound absorption coefficient was measured. Almost the same sound-absorbing characteristics as the first example were obtained.
  • the pierced apertures were formed with a drill upon producing the sound-absorbing material of the first comparative example; therefore, it took a long time for producing the sound-absorbing material.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Building Environments (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)
US11/723,850 2006-03-24 2007-03-22 Sound-absorbing material, production method of the same, and sound-absorbing panel Abandoned US20070235253A1 (en)

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JPP2006-082534 2006-03-24
JP2006082534A JP2007256750A (ja) 2006-03-24 2006-03-24 吸音材及び吸音材の製造方法並びに吸音パネル

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US20090246502A1 (en) * 2008-03-28 2009-10-01 Airbus Deutschland Gmbh Composite panel
US20100221570A1 (en) * 2005-12-23 2010-09-02 Jason Nadler Porous Metal Bodies Used for Attenuating Aviation Turbine Noise
US20130264145A1 (en) * 2010-10-25 2013-10-10 Jesper Nielsen Panel
US20150356962A1 (en) * 2014-06-06 2015-12-10 Industrial Technology Research Institute Metal foil with microcracks, method of manufacturing the same, and sound-absorbing structure having the same
CN111033608A (zh) * 2017-08-22 2020-04-17 富士胶片株式会社 隔音结构体及吸音面板
US10988924B2 (en) 2017-03-27 2021-04-27 Fujifilm Corporation Soundproof structure, sound absorbing panel, and sound adjusting panel
US20220148550A1 (en) * 2019-03-04 2022-05-12 Corning Incorporated Micro-perforated panel systems, applications, and methods of making micro-perforated panel systems
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CN105423451B (zh) * 2015-12-25 2018-05-01 广东美的制冷设备有限公司 室外机机箱、室外机及空调器
JP6458202B2 (ja) * 2016-03-29 2019-01-23 富士フイルム株式会社 防音構造、仕切り構造、窓部材およびケージ
JP2018141838A (ja) * 2017-02-27 2018-09-13 日東電工株式会社 吸音材

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US20100221570A1 (en) * 2005-12-23 2010-09-02 Jason Nadler Porous Metal Bodies Used for Attenuating Aviation Turbine Noise
US7963364B2 (en) * 2005-12-23 2011-06-21 Onera (Office National D'etudes Et De Recherches Aerospatiales) Porous metal bodies used for attenuating aviation turbine noise
US20080000717A1 (en) * 2006-06-29 2008-01-03 Patrick William P Anechoic visco-thermal liner
US7469770B2 (en) * 2006-06-29 2008-12-30 United Technologies Corporation Anechoic visco-thermal liner
US20090246502A1 (en) * 2008-03-28 2009-10-01 Airbus Deutschland Gmbh Composite panel
US8951623B2 (en) * 2008-03-28 2015-02-10 Airbus Operations Gmbh Composite panel
US8910748B2 (en) * 2010-10-25 2014-12-16 Soft Cells A/S Panel
US20130264145A1 (en) * 2010-10-25 2013-10-10 Jesper Nielsen Panel
US20150356962A1 (en) * 2014-06-06 2015-12-10 Industrial Technology Research Institute Metal foil with microcracks, method of manufacturing the same, and sound-absorbing structure having the same
US9251778B2 (en) * 2014-06-06 2016-02-02 Industrial Technology Research Institute Metal foil with microcracks, method of manufacturing the same, and sound-absorbing structure having the same
US11608291B2 (en) * 2016-11-04 2023-03-21 Corning Incorporated Micro-perforated panel systems, applications, and methods of making micro-perforated panel systems
US10988924B2 (en) 2017-03-27 2021-04-27 Fujifilm Corporation Soundproof structure, sound absorbing panel, and sound adjusting panel
CN111033608A (zh) * 2017-08-22 2020-04-17 富士胶片株式会社 隔音结构体及吸音面板
EP3675119A4 (en) * 2017-08-22 2020-08-26 FUJIFILM Corporation SOUND PROTECTION STRUCTURE AND SOUND INSULATION PANEL
US20220148550A1 (en) * 2019-03-04 2022-05-12 Corning Incorporated Micro-perforated panel systems, applications, and methods of making micro-perforated panel systems

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JP2007256750A (ja) 2007-10-04
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