JPH10102619A - Manufacture of inorganic fiber sound absorbing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve sound absorbing performance by sucking unhardened inorganic fiber filled in a forming mold having numerous clear holes from the outside of a forming die through the clear holes, forming projected portions, hardening and forming many projected portions on the incident surface, and improving the sound absorbing performance. SOLUTION: A formed die 201 comprises a main body 211 of forming die having numerous clear holes 211a at the positions corresponding to the projected portion of the inorganic fiber sound absorbing material, a lid body 212, and a core material 213. At the time of producing sound absorbing material, the inorganic fiber is filled in a layer shape in an incident direction of noise during the production of sound absorbing material and filled in the main body 211 in such a manner that its density becomes lower than that of the inorganic fiber at the rear side. Next, a forming die 201 is installed at a heating forming equipment, the inorganic fiber filled inside the main body 211 is sucked through clear holes 211a with a suction blower, projected portions are formed and heated and hardened by hot air or the like. By doing this, the inorganic fiber near the projected portions can be formed without being compressed, a drop in incident factor at the projected portion can be prevented and noise in a wide frequency range can be efficiently reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound-absorbing device provided below a sound-insulating wall, a viaduct of an elevated viaduct, an elevated railway or the like (in this specification, sometimes referred to simply as "viaduct"). The present invention relates to a method for producing a sound-absorbing material made of an inorganic fiber used in the present invention.

[0002]

2. Description of the Related Art With the increase in traffic volume and the size of vehicles, measures against traffic noise are strongly demanded, and in order to cope with this, soundproof walls provided with various sound absorbing members have been put to practical use. FIG. 16 shows a cross-sectional structure of a soundproof wall most commonly used at present. The soundproof wall is made of a surface plate 102 made of a metal plate material having a louver structure subjected to rust prevention treatment, a sound absorbing material 103 made of glass fiber wool whose surface is covered with a synthetic resin film 104, and a sound absorbing material 103 made of inorganic fiber.
A rear plate 105 made of a rust-proofed metal plate material provided with a space 106 in the back of the device 3 and a frame member 107 made of a rust-proofed metal plate material that seals the space 106 from a sound-absorbing member 101. This sound absorbing member 101
Is inserted into and fixed to a post made of rust-proof H-shaped steel or the like, or is directly fixed to a concrete side wall to form a soundproof wall.

[0003]

The sound absorbing member 101 used for a conventional soundproof wall has a synthetic resin film 104 on its surface.
Material made of inorganic fiber made of glass wool etc. covered with
03 is disposed so as to be in direct contact with the back surface of the front plate 102, so that the front plate 102 and the synthetic resin film 104
And the interface between the synthetic resin film 104 and the sound absorbing material 103 made of inorganic fiber and the sound absorbing effect of the synthetic resin film 104 itself can hardly be expected. Therefore, the sound absorbing member has a problem that the sound absorbing performance is low. Was.

In order to cope with this, the present inventors have previously proposed a sound absorbing member using an inorganic fiber sound absorbing material having a large number of protruding portions formed on a noise incident surface (Japanese Patent Application No. 8-19).
No. 5410).

[0005] By the way, as a method of manufacturing an inorganic fiber sound absorbing material having a large number of protrusions formed on the surface,
Using a molding die having a concave portion at a position corresponding to the projecting portion, after filling the uncured inorganic fibers with a predetermined pressure in the molding die so that the inorganic fibers are reliably filled into the concave portion of the molding die, There is a method in which the resin binder added to the inorganic fibers is cured by heating the molding die from the outside or supplying hot air into the molding die to obtain an inorganic fiber-made sound absorbing material having a required shape.

However, the sound absorbing material made of inorganic fibers produced by this method is intended to fill the mold with uncured inorganic fibers at a predetermined pressure so that the recesses of the mold are reliably filled with the inorganic fibers. In particular, the inorganic fibers around the protrusion are compressed, and the porosity is significantly reduced. When the sound absorbing member is formed by arranging the surface of the thus-produced inorganic fiber sound absorbing material on which a number of protrusions are formed as the noise incident surface, the noise incidence rate is reduced. It became clear that there was a problem.

The present invention solves the above-mentioned problems of the method for producing a sound absorbing material made of an inorganic fiber, and has a high noise incidence rate.
It is an object of the present invention to provide a method of manufacturing a sound absorbing material made of inorganic fibers having a large number of protrusions formed on a noise incident surface.

[0008]

In order to achieve the above object, a method of manufacturing a sound absorbing material made of inorganic fiber according to the present invention is directed to a method of manufacturing a sound absorbing material made of inorganic fiber having a large number of protrusions on a noise incident surface. Filling the uncured inorganic fibers in a mold having a through hole at a position corresponding to the protrusion, sucking the inorganic fibers from outside the mold through the through holes,
The method is characterized in that after the protruding portion is formed, it is cured.

In the method for producing a sound absorbing material made of inorganic fiber according to the present invention, a number of protrusions formed on the surface of the sound absorbing material made of inorganic fiber are formed by passing uncured inorganic fibers filled in a mold through through holes of the mold. Since it is formed by suction from the outside of the molding die, the inorganic fibers around the protruding portion are not compressed. Also, when the sound absorbing member is configured to be arranged so as to be the incident surface, the incidence rate of noise does not decrease.

In this case, the inorganic fibers can be filled into the mold in a layered manner so that the density of each inorganic fiber layer is different, and the inorganic fibers are layered in the noise incident direction. The inorganic fiber layer located on the noise incident side can be filled so that the density is lower than the density of the inorganic fiber layer on the back side.

[0011] This makes it possible to efficiently reduce noise in a wide range of frequencies. In particular, the density of the inorganic fiber layer located on the noise incident side is lower than the density of the inorganic fiber layer on the back side thereof. By filling as described above, the effect of reducing noise in a wide range of frequencies can be obtained while increasing the incidence rate of noise.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the method for producing a sound-absorbing material made of inorganic fiber of the present invention is provided below a viaduct floor slab shown in FIG. A description will be given with reference to FIGS. 1 to 4 based on a method of manufacturing a sound absorbing material made of an inorganic fiber used for a sound absorbing device.

As shown in FIG. 1, a molding die 201 used to manufacture the inorganic fiber sound absorbing material 13A having a large number of projecting portions 13a is formed as shown in FIG. 13a at a position corresponding to 13a.
It comprises a mold main body 211 having 1 a, a lid 212, and a core 213. Note that the shape of the through hole 211a is not limited to the circular shape in the present embodiment, and the shape can be arbitrarily set, for example, by forming a long hole in the vertical or horizontal direction.

The molding die body 2 constituting the molding die 201
11, the material of the lid 212 and the core material 213 is a non-perforated metal plate (a solid metal member in the case of the core material 213) or a large number of small holes (a hole having a much smaller diameter than the through hole 211a). Or a wire mesh (in the case of the core material 213, a hollow metal member having a large number of small holes or the like on its surface) or the like. In this case, in particular, the molding die body 211 sucks the uncured inorganic fibers filled in the molding die 201 described later from the outside of the molding die 201 through the through-holes 211a of the molding die body 211, so that the inorganic fiber sound absorbing material is formed. In order to smoothly form the protruding portion 13a on the surface of 13A, the protruding portion 13a is formed of a non-porous metal plate and divided so that the formed inorganic fiber sound absorbing material can be smoothly removed from the mold. It is desirable to make it possible.

A large number of protrusions 1 are
The process of manufacturing the inorganic fiber sound absorbing material 13A on which 3a is formed will be described. First, the inorganic fiber layer 13A-2 located on the noise incident side in the molding die body 211 is formed.
An uncured inorganic fiber such as glass wool or rock wool to which an appropriate amount of a resin binder is added (in this specification, it may be simply referred to as “inorganic fiber”) is used as the molding die body 21.
1 is filled along the inner peripheral surface (FIG. 2A). In this case, the inorganic fiber is the inorganic fiber layer 13A-2 after molding.
, For example, so as to have a density of 32 kg / m ³ . Next, an inorganic fiber which is to be the inorganic fiber layer 13A-3 located on the back side of the inorganic fiber layer 13A-2 is filled,
A core material 213 for forming the cavity 16A is provided at the center of the inorganic fiber layer 13A-3 (FIG. 2B). In this case, the inorganic fiber is the inorganic fiber layer 13A-3 after molding.
, For example, so as to have a density of 48 kg / m ³ . Next, an inorganic fiber layer 13A-1 located above the inorganic fiber layers 13A-2 and 13A-3, that is, on the back plate 15A side where the noise of the vehicle traveling through the viaduct passes through the viaduct floor slab and enters. Is filled with the inorganic fiber, and the lid 212 is placed on the top of the inorganic fiber (FIG. 2C). In this case, the inorganic fiber is the inorganic fiber layer 13A-1 after molding.
, For example, so as to have a density of 64 kg / m ³ .

As described above, the inorganic fibers are layered in the noise incident direction, and the density of the inorganic fiber layer located on the noise incident side is lower than the density of the inorganic fiber layer on the back side. The filled mold 201 is placed in a heating molding apparatus 2
02 (FIG. 3). This heat forming device 202
The lower chamber 202a and the upper chamber 2
02b, a suction blower 203 is connected to the lower chamber 202a, and a hot air generator 204 is connected to the upper chamber 202b. Then, first, the inside of the lower chamber 202a is made to have a negative pressure by driving the suction blower 203, and the inorganic fibers filled in the molding die body 211 are sucked through the through holes 211a formed in the molding die body 211,
The protrusion 13a, specifically, a protrusion having a height of about 3 to 10 mm is formed (FIG. 4). Then, by driving the hot air generator 204 while driving the suction blower 203, the hot air is forcibly passed through the inside of the mold 201, and the inorganic fibers are heated and hardened, and the sound absorbing material made of the inorganic fibers is removed. Molding. In the heating step,
The lid 212 is made of a metal plate or a wire mesh having a large number of small holes so that the superheated hot air can be forced to pass between the inorganic fibers filled in the mold 201 (projection). If a non-perforated metal plate is used for the lid 212 in the step of forming the portion 13a, the lid 212 is replaced with the above. Also, in the above description,
The step of forming the protrusion and the step of heating are performed separately, but is not limited to this. By simultaneously driving the suction blower 203 and the hot air generator 204 from the beginning, the step of forming the protrusion and the step of heating are performed. It can be done at the same time.
Also, by heating the forming die from outside without using hot air in the heating step, the inorganic fibers can be heated and cured, and the sound absorbing material made of inorganic fibers can be formed.

Next, an example in which the thus-produced sound absorbing material 13A made of inorganic fibers is applied to a sound absorbing device provided below a highly-bridged floor slab will be described. As shown in FIGS. 5 and 6, a sound absorbing device 7 is provided below the floor slab 51 of the viaduct 5 so as to form a predetermined work space 6 so as to cover substantially the entire lower surface of the floor slab 51. This sound absorbing device 7
Is also used as a permanent scaffold that is permanently installed for the worker to enter the work space 6 and repair the lower surface of the floor slab 51 or repair the steel material used for the bridge girder 52. At the time of repair work, it is provided so as to cover substantially the entire lower surface of the floor slab 51 so that there is no gap in which work materials such as paint, reinforcing steel, concrete, and the like, and work tools, etc. fall on the lower road 8. As a result, there is no need to assemble the scaffold each time repair work is performed as in the case of a conventional temporary scaffold.
Along with the favorable work environment of the repair work, it is possible to improve the work efficiency, and at the time of the repair work, paint,
Work materials such as steel bars and concrete, work tools, etc. do not fall, and therefore do not damage vehicles running on the road 8 below. Can be. The height H of the working space 6 is set to a height at which the repair work such as the repair of the lower surface of the floor slab 51 or the painting of the steel material used for the bridge girder 52 can be easily performed, for example, about 1 to 2 m. It is desirable to set.

The sound absorbing device 7 includes an erecting member 72 made of H-shaped steel disposed on the bridge girder 52 of the viaduct 5, and the erecting member 72
And a sound absorbing member 1A fixed via a fixing member 73.

As shown in detail in FIG. 8, the sound absorbing member 1A has a large number of openings made of aluminum punched metal or the like, and a bulge projecting outward in a strip shape extending along the longitudinal direction of the viaduct 5. Surface plate 12A made of a plate material having a portion formed
And a synthetic fiber non-woven fabric mat 1A between which the surface is covered with a synthetic resin film 14A such as polyvinyl fluoride to prevent scattering of the inorganic fibers.
1A, and a back plate 15A serving also as a scaffold plate having a large number of openings such as a perforated metal made of aluminum through a stainless wire mesh or a glass cloth 19A on the back surface of the inorganic fiber sound absorbing material 13A. It is arranged and fixed to the front plate 12A on a frame member 17A integrally formed with the back plate 15A by aluminum extrusion.

In this case, as described in the method of manufacturing the inorganic fiber sound absorbing material 13A, the inorganic fiber sound absorbing material 1A is used.
3A is divided into a plurality of inorganic fiber layers 13A-1,1 having different densities.
3A-2 and 13A-3 are combined to form a cavity 16A at the center of the inorganic fiber layer 13A-3. Specifically, the back plate 15A into which the noise of the vehicle traveling on the viaduct 5 penetrates and enters the floor slab 51 of the viaduct 5
In the inorganic fiber layer 13A-1 located on the side, an inorganic fiber layer of high density, for example, 64 kg / m ³ , which has a higher effect of reducing noise at lower frequencies than the other inorganic fiber layers 13A-2 and 13A- ³ , is used. It is desirable to use. Further, the inorganic fiber layers 13A-2 and 13A are provided so that the noise reduction effect of a wide range of frequencies can be obtained while increasing the noise incidence rate.
-3 is laminated in the noise incident direction, and the inorganic fiber layer 13A-2 located on the noise incident side has an inorganic fiber layer lower in density than the inorganic fiber layer 13A-3 on the back side;
For example, the inorganic fiber layer 13A-2 has 32 kg / m ³
It is preferable to use an inorganic fiber layer of 48 kg / m ^{3 for} the inorganic fiber layer of No. 1 and the inorganic fiber layer 13A-3.

As described above, the inorganic fiber sound absorbing material 13A is formed of a plurality of inorganic fiber layers 13A-1 and 13A- having different densities.
2, 13A-3, it is possible to efficiently reduce noise in a wide range of frequencies, and by forming a cavity 16A in the center of the inorganic fiber layer 13A-2, the sound absorption performance is improved. It is possible to reduce the amount of inorganic fiber used while improving the sound quality. Further, by disposing a stainless steel wire mesh or glass cloth 19A on the back of the inorganic fiber sound absorbing material 13A, the inorganic fiber sound absorbing material The synthetic resin film 14A covering the surface of the fiber layer 13A-1 can be prevented from being worn or damaged during repair work.

As shown in detail in FIG. 9, the synthetic fiber nonwoven fabric mat 11A is made of a synthetic resin material having weather resistance, for example, polyvinylidene chloride fiber, and is made of a synthetic resin material having appropriate weather resistance. Formed in a plate shape having flexibility by integrally bonding with a bridging agent. In this case, at the time of heat molding, at least the side facing the synthetic resin film 14A covering at least the inorganic fiber sound absorbing material 13A is formed. Projecting portion 11a, specifically, 3 to 10
It is desirable to form a protrusion of about mm. The shape of the protruding portion 11a is not limited to the circular protruding portion of the present embodiment, and the shape, height, and the like can be arbitrarily set, for example, formed in a vertical or horizontal band shape. .

The protrusion 11a of the synthetic fiber nonwoven fabric mat 11A and the protrusion 13a of the inorganic fiber sound absorbing material 13A
As a result, the interface between the synthetic resin nonwoven fabric mat 11A and the synthetic resin film 14A covering the surfaces of the inorganic fiber sound absorbing material 13A, the synthetic resin film 14A and the inorganic fiber sound absorbing material 13
The sound absorbing effect at the boundary surface of A and the synthetic resin film 14A itself can be expected, and the sound absorbing performance of the sound absorbing member 1A can be improved.

FIG. 10 shows a modified example of the inorganic fiber sound absorbing member. This inorganic fiber sound absorbing member 1A 'forms a space 18A between the surface plate 12A of the sound absorbing member 1A and the synthetic fiber nonwoven fabric mat 11A shown in FIG. 8, and the inorganic fiber sound absorbing material 13A' having a different density. Inorganic fiber layer 13
A-1 and the inorganic fiber layer 13A-2 (single layer) are combined to form a hollow 16 in the center of the inorganic fiber layer 13A-2.
A is formed, and the other basic configuration is the same as that of the sound absorbing member 1A shown in FIG. Thus, the surface plate 12
By forming the space 18A between A and the synthetic fiber nonwoven fabric mat 11A, the effect of reducing high frequency noise can be improved. In addition, this inorganic fiber sound absorbing material 13
A ′ can be produced by a method basically similar to that of the above-mentioned inorganic fiber sound absorbing material 13A.

As shown in FIG. 5 and FIG.
On both outer sides of the sound absorbing device 7 in the width direction, a strut 95 made of H-shaped steel whose ends are fixed to the floor slab 51 and the sound absorbing device 7 is provided, and the strut 95 is provided with the fall prevention device 9. The fall prevention device 9 is used to prevent work materials such as paints, reinforcing bars, and concrete, work tools, and the like from dropping on the road 8 and the worker from falling down during repair work on the side wall 53 and the like of the viaduct 5. The extension is provided along the longitudinal direction of the viaduct 5 and is usually installed at a storage position below the floor slab 51 of the viaduct 5, and an adjusting tool 92 such as a chain is used during repair work. By operating it, it swings around the hinge 91 and is installed at the projecting position 9 ′ outside the lower side wall 53 of the viaduct 5. The overhang width W of the fall prevention device 9 is such that when repairing the side wall 53 of the viaduct 5, work materials such as paint, reinforcing steel, concrete, work tools, etc., fall on the road 8, or the worker falls down. It is desirable that the width is set to, for example, about 1 m, which can prevent the occurrence of such a phenomenon. Further, in the present embodiment, the fall prevention device 9 is provided with a fixed portion 9 for convenience of setting the height H of the work space 6 to be large.
6, the height H of the work space 6 and the fall prevention device 9
Depending on the overhang width W, the fixed portion 96 can be omitted.

The fall prevention device 9 is provided with a sound absorbing member 1B on a frame member 93 made of rust-proofed steel or aluminum so as to reduce the noise of a vehicle traveling on a road below the viaduct. Although arranged and configured, the sound absorbing material made of inorganic fiber used for the sound absorbing member 1B can be manufactured by basically the same method as the sound absorbing material 13A made of inorganic fiber.

The sound-absorbing material made of inorganic fiber produced by the method of the present invention can be used not only for the sound-absorbing device and the fall-preventing device provided below the viaduct floor slab, but also for a general sound-absorbing member of a soundproof wall. . 11 to 15 show examples thereof.

The sound absorbing member 1 shown in FIG. 11 has a surface plate 12 made of a metal plate material having a large number of openings, such as a rustproof expanded metal, a punched metal, and a louver structure.
A synthetic fiber nonwoven fabric mat 11 is disposed between the fiber and a sound absorbing material 13 made of an inorganic fiber whose surface is covered with a synthetic resin film 14 such as polyvinyl fluoride in order to prevent the scattering of the inorganic fiber. It is composed of unit blocks covered with a frame member 17 made of a rust-treated metal plate.

Among these, the synthetic fiber nonwoven fabric mat 11 is
The one shown in FIG. 9 described above can be used.

The sound absorbing material 13 made of inorganic fiber is a material obtained by molding inorganic fibers by a method basically similar to that of the sound absorbing material 13A made of inorganic fiber. In this case,
Numerous protrusions 1 on the side facing the synthetic fiber nonwoven fabric mat 11
3a, specifically, a protrusion of about 3 to 10 mm is formed by suctioning the inorganic fiber from the outside of the mold through a through hole formed in the mold. In addition, the sound absorbing material 13 made of an inorganic fiber can also form a cavity in the center thereof, thereby reducing the amount of the inorganic fiber used without deteriorating the sound absorbing performance.

This sound absorbing member 1 is, as shown in FIG.
The sound absorbing member 1 is provided with a space 3 in front of a side wall 2 made of concrete or the like.
The soundproof wall can be configured by arranging the openings. In this case, when arranging the sound absorbing member 1 on the front surface of the side wall 2, although not particularly limited, the sound absorbing member 41 is fixed to the angle steel 41 vertically fixed to the side wall 2 by an anchor bolt or the like via a fixing bracket 42. One frame member 17 is fixed with bolts. Then, the sound absorbing members 1 are sequentially stacked up to a predetermined height to construct a soundproof wall.

As shown in FIG. 13, the sound absorbing member 1 is provided with a back plate 15 made of a rust-proof metal plate with a space 16 provided on the back of the sound absorbing member 1. Can be configured as a unit block 10 hermetically sealed by a frame member 17a made of a metal plate material subjected to a rustproofing process. In this case, the soundproof wall is constructed by inserting and fixing the unit block 10 to a post made of rust-proofed H-shaped steel or the like, or by directly fixing it to the side wall made of concrete.

FIG. 14 shows a first modification of the sound absorbing member 1. As shown in FIG. This sound absorbing member 1 ′ has a space 1 between the surface plate 12 of the sound absorbing member 1 shown in FIG.
The other basic configuration is the same as that of the sound absorbing member 1 shown in FIG. 11, including the method of manufacturing the sound absorbing material 13 made of inorganic fiber.

In this case, a large-diameter weather-resistant synthetic resin thread, for example, a nylon thread having a diameter of about 1 mm, is entangled in the space 18 as needed to hold the space 18. A spacer formed in a flexible plate shape having an extremely high porosity (not shown) by fusing the nylon yarn itself or integrally bonding it with a bridging agent made of a synthetic resin material having appropriate weather resistance. )
Are arranged at appropriate intervals.

By forming the space 18 between the surface plate 12 and the synthetic fiber nonwoven fabric mat 11, the effect of reducing high frequency noise can be improved.

FIG. 15 shows a second modification of the sound absorbing member of the present invention. The sound absorbing member 1 ″ is a combination of the inorganic fiber sound absorbing material 13 ″ of the sound absorbing member 1 shown in FIG. 1 and a plurality of inorganic fiber layers 13-1 and 13-2 having different densities. Other basic configurations including the method of manufacturing the sound absorbing material 13 are the same as those of the sound absorbing member 1 shown in FIG.

As described above, by composing the inorganic fiber sound absorbing material 13 ″ by combining a plurality of inorganic fiber layers 13-1 and 13-2 having different densities, it is possible to efficiently reduce noise in a wide range of frequencies. it can.

In this case, the inorganic fiber layers 13-1 and 13-2 of the sound absorbing material 13 "made of the inorganic fiber are made of a noise so that the noise reduction effect of a wide range of frequencies can be obtained while increasing the incidence rate of the noise. Layered in the incident direction of
The inorganic fiber layer 13-1 located on the noise incident side has an inorganic fiber layer having a lower density than the inorganic fiber layer 13-2 on the back side, for example, the inorganic fiber layer 13-1 has 32 kg / m2.
³ of the inorganic fiber layer, the inorganic fiber layer 13A-2, it is preferable to use the inorganic fiber layer 48 kg / m ^3.

The sound absorbing member 1 'shown in FIG. 14 and the sound absorbing member 1 "shown in FIG. 15 can be used in the same manner as the sound absorbing member 1 shown in FIG.

[0040]

According to the method for producing an inorganic fiber-made sound absorbing material of the present invention, a plurality of projections formed on the surface of the inorganic fiber-made sound absorbing material are filled with uncured inorganic fibers in a molding die. Since the holes are formed by suction from the outside of the molding die through the through holes, the inorganic fibers around the protrusions are not compressed, and thus a large number of protrusions of the inorganic fiber sound absorbing material are formed. Also, when the sound absorbing member is configured by disposing such a surface as a noise incident surface, a noise absorbing member with high sound absorbing performance can be obtained without a decrease in the noise incidence rate.

Also, by filling the forming mold with inorganic fibers in layers and with different densities of the inorganic fiber layers, noise in a wide range of frequencies can be efficiently reduced. By filling the density of the inorganic fiber layer located on the incident side so as to be lower than the density of the inorganic fiber layer on the back side, a noise reduction effect of a wide range of frequencies can be obtained while increasing the noise incidence rate. be able to.

[Brief description of the drawings]

FIG. 1 is an external perspective view in which a part of a mold used in a method for producing a sound absorbing material made of inorganic fibers of the present invention is partially broken.

FIG. 2 is an explanatory diagram showing a step of filling inorganic fibers in the method for producing a sound absorbing material made of inorganic fibers of the present invention.

FIG. 3 is a cross-sectional view showing a heat molding apparatus used in the method for producing an inorganic fiber sound absorbing material of the present invention.

FIG. 4 is an explanatory view showing a step of forming a projecting portion in the method for producing a sound absorbing material made of inorganic fibers of the present invention.

FIG. 5 is a schematic perspective view of a viaduct provided with a sound absorbing device and a fall prevention device.

FIG. 6 is a sectional view of the main part.

FIG. 7 is a sectional view showing an example of a sound absorbing member used in the sound absorbing device.

FIG. 8 is a detailed sectional view showing an example of a sound absorbing member.

9A and 9B show a synthetic fiber nonwoven fabric mat, wherein FIG. 9A is a plan view and FIG. 9B is a cross-sectional view taken along line AA of FIG. 9A.

FIG. 10 is a sectional view showing a modification of the sound absorbing member.

FIG. 11 shows an example of a sound absorbing member, (a) is a front view,
(B) is a side longitudinal sectional view, and (c) is a plane transverse sectional view.

12 shows an example of a soundproof wall using the sound absorbing member shown in FIG. 11, (a) is a plane cross-sectional view, (b) is a front view,
(C) is a sectional view taken along line BB of (b).

13 shows an example of a soundproof wall using the sound absorbing member shown in FIG. 11, (a) is a front view, and (b) is a side vertical sectional view.

14A and 14B show a first modified example of the sound absorbing member, in which FIG. 14A is a front view, FIG. 14B is a side longitudinal sectional view, and FIG. 14C is a plane transverse sectional view.

15A and 15B show a second modified example of the sound absorbing member, wherein FIG. 15A is a front view, FIG. 15B is a side vertical sectional view, and FIG.

FIG. 16 is a cross-sectional view showing the structure of a conventional soundproof wall.

[Explanation of symbols]

1, 1 ', 1 ", 1A, 1A', 1B Sound absorbing member 11, 11A Synthetic fiber nonwoven fabric mat 11a Projection 12, 12A, 12B Surface plate 13, 13-1, 13-2, 13A, 13A-1, 13
A-2, 13A-3 Sound absorbing material made of inorganic fiber 13a Projecting portion 14, 14A, 14B Synthetic resin film 15 Back plate 15A, 15B Back plate 16 Space 16A Cavity 18, 18A Space 2 Side wall 3 Space 5 Viaduct 51 Floor slab 52 Bridge beam 53 Side wall 7 Sound absorbing device 8 Road 9 Fall prevention device 201 Mold 211 Mold main body 211a Through hole 212 Lid 213 Core material

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Atsutaka Fujii 3-2-220 Minamimikunigaoka-cho, Sakai-shi, Osaka

Claims (3)

[Claims] 1. A method of manufacturing a sound absorbing material made of inorganic fibers having a large number of protrusions on a noise incident surface, wherein uncured inorganic fibers are filled in a mold having a through hole at a position corresponding to the protrusions. A method for producing a sound-absorbing material made of an inorganic fiber, wherein the inorganic fiber is sucked from the outside of a molding die through the through-hole to form the projecting portion and then is cured. 2. An inorganic fiber layered in a molding die, and
The method for producing a sound absorbing material made of inorganic fibers according to claim 1, wherein the packing is performed so that the densities of the inorganic fiber layers are different. 3. The inorganic fibers are layered in the noise incident direction.
And, the density of the inorganic fiber layer located on the noise incident side,
3. The method for producing a sound absorbing material made of inorganic fibers according to claim 2, wherein the filling is performed so that the density is lower than the density of the inorganic fiber layer on the back side.