JP3478101B2 - Sound absorbing device - Google Patents

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, and for example, it surrounds an engine of an automobile to absorb sound from the engine, absorbs noise of an automobile traveling along a highway, and absorbs noise from a building. The present invention relates to a sound absorbing device that is suitable for being mounted on a wall and absorbing a sound that enters the inside of a building or a sound that leaks to the outside.

[0002]

2. Description of the Related Art A sound absorbing device has been proposed in which a gap is provided in a shielding plate surrounding an engine, and a sound absorbing material curved in a convex shape is attached to the inside of the shielding plate (actually, 3-1109).
59 publication).

[0003]

Since the sound absorbing material is a solid type, a considerable amount of sound absorbing material is required to obtain a predetermined effect, which is disadvantageous in cost.

The present invention provides a sound absorbing device which can achieve high effects with a minimum amount of sound absorbing material.

[0005]

A sound absorbing device according to the present invention comprises a substrate made of a plate material having a substantially square planar shape and four sides, and two opposite sides of the substrate. And a sound absorbing material disposed over at least one side of the substrate with an air layer interposed. The sound absorbing material is formed in a curved shape that is gradually curved away from the substrate from each of the two sides toward the center between the two sides, and the curved shape extends between the remaining two sides. ing. Further, in this sound absorbing material, in the sound absorbing material, the center of the thickness of the sound absorbing material at the portion farthest from the substrate is 1/4 of the wavelength of the sound to be absorbed by the sound absorbing material from the surface of the substrate. The dimensions are set so that the distance is obtained.

When the sound wave reaches the sound absorbing material from the direction intersecting with the sound absorbing material, the sound wave passes through the sound absorbing material and reaches the substrate through the air layer. After that, it is reflected by the substrate, reaches the sound absorbing material through the air layer again, and passes through the sound absorbing material again. On the other hand, when the sound wave enters the sound absorbing material from the tangential direction, the sound wave propagates inside the sound absorbing material and then exits from the sound absorbing material.

Since there is an air layer between the substrate and the sound absorbing material,
The amount of sound absorbing material used can be reduced. by the way,
The sound absorbing effect of the sound absorbing material becomes higher as the particle velocity of the sound wave passing through the sound absorbing material becomes higher, and becomes higher as the passing distance through the sound absorbing material becomes longer. Therefore, of the curved shape of the sound absorbing material,
The curved shape is determined so that the particle velocity of the sound wave becomes the highest at the position where it becomes the highest from the substrate, and the sound absorbing device is installed so that the sound wave from the sound source enters the position where the sound absorbing material becomes the highest from the normal direction. Therefore, the highest sound absorbing effect can be obtained. Also, a high sound absorbing effect can be obtained by smoothly bending the sound absorbing material so that the sound wave entering the sound absorbing material from the tangential direction propagates in the sound absorbing material as long as possible.

The sound-absorbing material is attached to these two sides from each of the two sides.
Since it is curved so as to gradually separate from the substrate as it goes to the center between the two sides, a smooth curve can be obtained. As a result, the distance that the sound wave that has passed through the sound absorbing material and reflected by the substrate reaches the sound absorbing material from the substrate again can be made close to the distance at which the particle velocity of the sound wave is the fastest, and the curved shape can be used for the two remaining portions of the substrate. Because it extends between the sides,
A good sound absorbing effect can be obtained over a wide range.

The sound absorbing device according to the present invention also includes a substrate made of a plate material having a substantially rectangular planar shape and having four sides, and one of the two opposing sides of the substrate above the other side. Alternatively, the sound absorbing member is provided facing downward and is located on at least one side of the substrate with an air layer interposed.
The sound absorbing material is formed in a curved shape that is gradually curved away from the substrate from one of the two sides toward the other side, and the curved shape extends between the remaining two sides. Also, keep this sound absorbing material on the side of the other side.
The distance from the surface of the substrate to the center of the thickness of the sound absorbing material is 1/4 of the wavelength of the sound to be absorbed by the sound absorbing material.
The dimensions are set so that

Although the sound absorbing material has substantially the same function and effect as the sound absorbing device having two sides, the present invention is further effective in eliminating the waste of the sound absorbing material when the sound source is fixed in one place. Can absorb sound.

The sound absorbing device according to the present invention also includes a substrate made of a plate material, and a sound absorbing material that is raised from the peripheral edge of the substrate and is positioned on at least one side of the substrate with an air layer interposed. The sound absorbing material is curved so as to gradually separate from the substrate as it goes from the peripheral edge toward the center. In addition, this sound absorbing material was farthest from the substrate.
The distance at the site to the center of the thickness of the substrate or al the sound absorbing material, the first wavelength of the sound to be absorbed by the sound absorbing material
The size is determined to be / 4.

When the substrate has a rectangular shape, a circular shape, an elliptical shape or the like and is relatively small, the sound absorbing material is raised from the peripheral edge of the substrate to form a sound absorbing device, and such an independent sound absorbing device is used alone or in a plurality. Line up and absorb sound.

When using a plurality of independent sound absorbing devices,
Since the arrangement can be arbitrarily selected, it becomes easy to absorb sound according to the sound source. Further, the sound absorbing material of each sound absorbing device is effective for the sound wave passing through the sound absorbing material and the sound wave propagating through the sound absorbing material as in the above-mentioned invention, and can absorb the sound well.

The sound absorbing device according to the present invention also comprises a plurality of cells each having a plate material arranged at the peripheral portion and the bottom portion and having the top portion as an opening, and the sound absorbing material arranged at the opening of each cell. The sound absorbing material is separated from the bottom by a distance corresponding to substantially a quarter of the wavelength of the sound to be absorbed by the sound absorbing material, and the opening is formed to be smaller than the wavelength. .

A sound wave passing through a cell having a cross section smaller than the wavelength travels straight without causing reflection in the peripheral portion and becomes a plane wave. Therefore, the sound wave that has passed through the sound absorbing material and reached the bottom through the air layer in the cell is reflected only by the bottom portion, reaches the sound absorbing material through the air layer again, and passes there.

The sound absorbing material is separated from the bottom by a distance corresponding to substantially one quarter of the wavelength of the sound to be absorbed by the sound absorbing material, but this distance is a place where the sound wave vibrates as an antinode. It is the place where the particle velocity of the sound wave reflected at the bottom is the highest and the energy of the sound wave is the highest.
The sound absorbing material effectively attenuates the highest energy, and can absorb the sound satisfactorily. Further, since the sound absorbing material is positioned with the air layer interposed, the amount thereof can be reduced.

The sound absorbing device according to the present invention also comprises a plurality of cells each having a plate member arranged in the peripheral portion and having openings at the top and bottom thereof, and a sound absorbing member arranged in each of the openings of each cell. The sound absorbing material at the top and the sound absorbing material at the bottom are separated by a distance corresponding to substantially one half of the wavelength of the sound to be absorbed by these sound absorbing materials, and the opening is smaller than the wavelength. Is formed.

The sound wave goes straight without causing reflection in the peripheral portion of the cell and becomes a plane wave. Therefore, the sound wave that has passed through the sound absorbing material at the top and passed through the air layer in the cell to reach the sound absorbing material at the bottom is partially reflected by only the sound absorbing material at the bottom, and the rest passes through the sound absorbing material at the bottom. The sound waves reflected by the sound absorbing material at the bottom, passing through the air layer again, and reaching the sound absorbing material at the top pass therethrough.

The sound absorbers at the top and the bottom are separated from each other by a distance which corresponds to substantially one-half the wavelength of the sound to be absorbed by the sound absorbers, in which case the sound waves are belly at the top and bottom. The particle velocity becomes the fastest in the antinode. As a result, the sound absorbing material at the top and the bottom effectively attenuates the highest energy of the sound wave, and can absorb the sound satisfactorily. Further, since the sound absorbing material is positioned with the air layer interposed, the amount thereof can be reduced.

The sound absorbing device according to the present invention is also a cell formed by arranging plate members at a peripheral portion and a bottom portion, and arranging a plate member having an opening at a top portion so that the sectional shape is substantially circular. There is a partitioning material that hangs from the top in the vicinity of the opening of the top and that extends from the peripheral portion to the center in the radial direction, and the sound entering from the opening propagates in the circumferential direction and the partitioning material A plurality of cells formed so as to be reflected by the cell and returned to the opening, and a sound absorbing material disposed in the opening of each cell. The opening of the cell and the partition member are separated by a distance corresponding to substantially a quarter of the wavelength of the sound to be absorbed by the sound absorbing material, and the opening is smaller than the wavelength. Has been formed.

It can be expected that a sound wave passing through a circular cell having an opening smaller than the wavelength travels straight without causing reflection at the peripheral portion and becomes a plane wave. Therefore, the sound wave that has passed through the sound absorbing material and reached the partitioning material through the air layer in the cell is reflected only by the partitioning material, reaches the sound absorbing material through the air layer again, and passes through here.

The sound absorbing material is separated from the partition material by a distance corresponding to substantially one quarter of the wavelength of the sound to be absorbed by the sound absorbing material, but this distance is a portion where the sound wave vibrates as an antinode. The particle velocity of the sound wave reflected by the partition material is the highest, and the energy of the sound wave is the highest. The sound absorbing material effectively attenuates the highest energy, and can absorb the sound satisfactorily. Further, since the sound absorbing material is positioned with the air layer interposed, the amount thereof can be reduced.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the principle of the present invention will be described with reference to the schematic FIGS. When the incident wave B of the sound wave traveling in the A direction reaches the sound absorbing material 30, the incident wave B passes through the sound absorbing material 30 and reaches the substrate 34 via the air layer 32. After that, the incident wave B is reflected by the substrate 34 to become a reflected wave C, reaches the sound absorbing material 30 again through the air layer 32, and passes through the sound absorbing material 30. When the sound wave is reflected by the substrate 34, the sound wave vibrates from the substrate 34 so that an antinode of vibration comes to a portion corresponding to a quarter of the wavelength λ, and the particle velocity of the acoustic wave in the antinode becomes the highest. This is because the sound wave has a large energy, so if the sound wave is passed through the sound absorbing material 30 here, the sound wave can be greatly attenuated.

Next, when the sound wave traveling in the D direction enters the sound absorbing material 30 from the tangential direction, the sound wave propagates in the sound absorbing material 30 if the sound absorbing material 30 is smoothly curved. Therefore, if the curved shape of the sound absorbing material 30 is determined so that the sound wave travels in the sound absorbing material 30 as long as possible, the sound wave can be greatly attenuated. An arc is usually suitable for this.

As shown in FIG. 2, when an incident wave B of a sound wave traveling in the direction A passes through the sound absorbing material 36 and further into a cell 37 having a cross section smaller than the wavelength of the sound wave, the incident wave B Goes straight without causing reflection in the periphery of the cell 37 and becomes a plane wave. Therefore, the incident wave B that has passed through the sound absorbing material 36, passed through the air layer 39 in the cell, and reached the bottom portion 38.
Is reflected only by the bottom portion 38 to become a reflected wave C, and reaches the sound absorbing material 36 again via the air layer 39. When the sound wave is reflected by the bottom portion 38, the sound wave vibrates so that an antinode of vibration comes from the bottom portion 38 to a portion corresponding to a quarter of the wavelength λ, as described above, and the particle velocity of the sound wave in the antinode is Be the fastest. This is because the sound wave has a large energy, so if the sound wave is passed through the sound absorbing material 36 here, the sound wave traveling in the A direction can be greatly attenuated.

Referring to FIG. 3 in a sectional state and FIG. 4 in a perspective state, the sound absorbing device 40 has a substrate 42 which is a plate material having a substantially rectangular planar shape and four sides, and a substrate 4.
The sound absorbing material 46 is disposed over two opposite sides of the substrate 42 and is located on at least one side of the substrate 42 with the air layer 44 interposed.

In the illustrated embodiment, the substrate 42 is made of a rectangular hard plate and has four sides 48, 49, 50 and 51. The substrate 42 can be made of a hard resin such as polypropylene, a steel plate, or a metal such as an aluminum plate. The two sound absorbing members 46 are arranged over the two sides 48 and 49. Each sound absorbing material 46 has two sides 48, 4
9 is formed in a curved shape that is gradually curved away from the substrate 42 toward the center between these two sides, and this curved shape is formed on the remaining two sides 50, 51.
It stretches in between. That is, between the two sides 50 and 51, the sound absorbing material 46 has substantially the same shape in any part. Two
Each of the sound absorbing members 46 has a symmetrical shape with respect to the substrate 42 and has an arc shape having the substrate 42 as a chord. The sound absorbing material 46 is formed by molding a material known per se, such as glass wool, and appropriately adhering the material so that the shape can be maintained.
It is adhered or screwed to the substrate 42. A material such as felt or urethane can be used as the sound absorbing material 46. The thickness of the sound absorbing material 46 can be set to, for example, about 10-30 mm.

In the sound absorbing material 46, the center of the thickness of the sound absorbing material at the portion farthest from the substrate 42 is λ from the surface of the substrate 42.
The dimensions are set so that the distance is / 4. Where λ
Is a wavelength of sound to be absorbed by the sound absorbing material 46. Sound absorbing material 46
A plurality of partition plates 54 in the air layer 44 between the substrate 42 and the
It is preferable to attach these partition plates so that they are equally spaced between the two sides 50, 51. The partition plate 54 is
It can be made of hard resin or metal. This is sound absorbing material 4
The shape maintenance function of 6 and the function of adjusting the flow of sound are fulfilled.

The sound absorbing device 60 shown in cross section in FIG.
A substrate 62 made of a plate material having a substantially rectangular plane shape and having four sides, and two opposing sides 6 of the substrate.
The sound absorbing material 66 is disposed from one of 68 and 69 to the upper side or the lower side of the other side 69, and is located on at least one side of the substrate 62 with the air layer 64 interposed. The substrate 62 is rectangular like the substrate 42 of FIG.

In the illustrated embodiment, two sound absorbing materials 66 are arranged above and below the substrate 62. Each sound absorbing material 66
Is one side 6 of the two sides 68, 69 of the substrate 62.
The curved shape is formed so as to gradually separate from the substrate 62 as it goes from 8 to the other side 69, and this curved shape extends between the remaining two sides, that is, in the direction perpendicular to the paper surface of FIG. The distance from the surface of the substrate 62 on the side 69 side to the center of the thickness of the sound absorbing material 66 is dimensioned to be λ / 4. Here, λ is the wavelength of the sound to be absorbed by the sound absorbing material 66. The substrate 62 and the sound absorbing material 66 can be formed of the same materials as those described above.

The sound absorbing device 70 shown in FIG. 6 in a perspective view is
A board 72 made of a plate material and a sound absorbing material 76 that is raised from the peripheral edge of the board 72 and is located on at least one side of the board 72 with an air layer 74 interposed therebetween. The sound absorbing material 76 is curved so as to gradually separate from the substrate 72 from the peripheral edge toward the center. The substrate 72 and the sound absorbing material 76 can be formed of the same materials as those described above.

In the illustrated embodiment, the substrate 72 is a disk, and the sound absorbing material 76 has a round roof shape, that is, a dome shape above the substrate 72. The distance from the substrate 72 to the center of the thickness of the sound absorbing material 76 at the portion where the sound absorbing material 76 is farthest from the substrate 72 is determined to be λ / 4. Here, λ is the wavelength of the sound to be absorbed by the sound absorbing material 76. Substrate 72 may be square, elliptical or other shape instead of a disk. In the sound absorbing device shown in FIGS. 3 to 5, the curved shape of the sound absorbing material is continuous over a certain length, whereas in the sound absorbing device of FIG. 6, there is no such continuous connection.

The sound absorbing device 40 can be arranged and used as shown in FIGS. 7 to 13. Referring to FIG. 7 showing the front state and FIG. 8 showing the plane state, the sound absorbing device 4
0 is arranged in the engine room 82 to absorb the sound from the engine 80. The sound absorbers 40 are arranged in three rows on the left side and the right side of the engine 80. The left side arrangement and the right side arrangement are such that the sound absorbing apparatuses 40 are oblique so that the substrate 42 faces upward with respect to the engine 80. It is symmetrical. Further, the sound absorbing devices 40 are arranged in front of and behind the engine 82.

Referring to FIG. 9 showing the front view, the sound absorbing device 40 is arranged in the enclosure 86 to absorb the sound from the sound source 84. The sound absorbing devices 40 are arranged in three rows above and below the left and right sides of the sound source 84. The arrangement of the left side and the arrangement of the right side are the sound absorbing devices 4 such that the substrate 42 is horizontal.
0 is horizontal and symmetrical.

Referring to FIG. 10 showing the front view, the sound absorbing device 40 is arranged inside the enclosure 86 to absorb the sound from the sound source 84. The sound absorbers 40 are arranged in three rows, one on the left side and one on the right side of the sound source 84. The left side arrangement and the right side arrangement mean that the sound absorbing apparatus 40 is inclined so that the substrate 42 faces downward with respect to the sound source 84. It is symmetrical.

Referring to FIG. 11 showing the front view, the sound absorbing device 40 is arranged inside the enclosure 90 to absorb the sound from the sound source 88. 1 on each of the left and right sides of the sound source 88
The sound absorbers 40 are arranged in rows, but the left-hand arrangement and the right-hand arrangement are symmetrical with respect to the sound absorbing device 40 so that the substrate 42 faces upward with respect to the sound source 88.

Referring to FIG. 12 showing the front view, the sound source 92 is an oil pan on the lower side of the engine, and the sound absorbing devices 40A are arranged in one row on the left and right sides of the oil pan 92, respectively. The sound absorbing device 40A is a modification of the sound absorbing device 40, and is the same as the sound absorbing device 40 in that it includes a substrate 42A, an air layer 44, and a sound absorbing material 46A.
The difference is that the substrate 42A is made of a rubber material.
Since the substrate 42A is made of a rubber material, the sound absorbing device 40
A has flexibility as a whole. Therefore, in the illustrated embodiment, the entire sound absorbing device 40A is bent, and the sound absorbing material 46A is arranged in contact with the oil pan 92. Sound absorbing device 40
The punching metal 94 is arranged on the lower side of A and the sound absorbing device 4 is provided.
It is preferred to protect 0A.

Referring to FIG. 13 showing the front view, the sound source 92 is an oil pan and the sound absorbing device 40 is an oil pan 9.
Substrates 42 are arranged horizontally in a row on each of the left and right side portions of the substrate 2. It is preferable to arrange the punching metal 94 below the sound absorbing device 40.

Referring to FIG. 14 showing the front surface of the sound absorbing device 60, the sound source 9 is arranged so as to be symmetrical with respect to the sound source 96.
Substrates 62 are arranged in a row on each of the left and right side portions of 6 so as to be horizontal. When the sound source 96 is relatively small, the sound absorbing device 60 can be used to reduce the amount of the sound absorbing material as compared with the case where the sound absorbing device 40 is used. Comparing FIG. 14 and FIG. 13, the sound absorbing device 6
It can be seen that 0 can be approximately half the size of the sound absorber 40.

Referring to FIG. 15 showing the front state, the sound absorbing device 60A is a modified form of the sound absorbing device 60, and is the same as the sound absorbing device 60 in that it includes a substrate 62, an air layer 64, and a sound absorbing material 66. However, in the sound absorbing device 60A, the sound absorbing material 6
6 is provided only below the substrate 62. Sound absorbing device 6
OAs 0A are arranged in one row on the left and right sides of the sound source 96 so that the board 62 is horizontal and the sound absorbing material 66 is on the lower side.

The arrangements shown in FIGS. 7 and 9 to 11 can be replaced with the arrangements shown in FIGS. 14 and 15, and the arrangement shown in FIG. 12 can be obtained by making the substrate 62 from a rubber material. You can also do it.

The sound absorbing device 70 is mounted, for example, on a soundproof wall built along a road for automobiles in a state where a substrate 72 is in close contact with the soundproof wall, and a large number of such sound absorbing devices are arranged along the road. It can be used by arranging in a plurality of columns in the vertical direction.

The sound absorbing device 100 shown in FIG. 16 in a perspective state and in FIG. 17 in a sectional view has a plurality of cells 102 in which plate members are arranged at the peripheral portion and the bottom portion, and the top portions are formed as openings.
Sound absorbing material 104 arranged in the opening of each cell. The sound absorbing material 104 is separated from the bottom by a distance corresponding to substantially one quarter of the wavelength of the sound to be absorbed by the sound absorbing material. The opening is formed to be smaller than the wavelength.

In the illustrated embodiment, the cell 102 has a perimeter 1
This is a form in which the bottom portion 107 is attached by making 06 a square tube. Such cells 102 are arranged two-dimensionally in the horizontal direction, and the sound absorbing material 104 is arranged in the opening at the top so that the sound absorbing device 10 is provided.
0 is formed. The sound absorbing material 104 is located such that the distance from the surface of the bottom portion 107 to the center of the thickness of the sound absorbing material 104 is ¼ of the wavelength λ. The peripheral portion 106 and the bottom portion 107 can be obtained by injection molding a hard resin. The length of one side of the peripheral portion 106 of the cell 102 is, for example, 340 m / s for the speed of sound and 10 for the frequency of the sound to be absorbed by the sound absorbing material.
At 00 Hz, the wavelength of the sound is 34 cm, so it can be set to about 1/5 to 1/10 of the wavelength.

The sound absorbing material 104 is separated from the bottom by a distance corresponding to substantially one quarter of the wavelength λ of the sound to be absorbed by the sound absorbing material, the size of which depends on the shape of the opening. It can be determined as follows. As shown in FIG. 18, when the cell 108 has an oblique opening, the sound absorbing material 1
10 is arranged diagonally. In this case, the sound absorbing material 110
It suffices that the midpoint of the length of is at the distance from the bottom portion 109. When there is an intermediate cell 112 as shown in FIG. 7C, the sound absorbing material 114 provided in the intermediate cell 112 is out of the distance, but the sound absorbing materials 110 attached to the cells 108 on both sides are set to the distance. As shown in FIG. 19, when the peripheral portion 118 forming the cell 116 extends obliquely from the bottom portion 119, the sound absorbing material 120 has the actual length of the peripheral portion 118, that is, the peripheral portion 1 extending from the bottom portion 119 to the sound absorbing material 120.
The length of 18 is determined to be the distance.

The sound absorbing device 130 shown in FIG. 20 in a sectional state.
The plate material is arranged on the peripheral portion 132 and the bottom portion 133, and includes a plurality of cells 134 having openings at the tops thereof, and a sound absorbing material 136 arranged at the openings of the cells. The sound absorbing material 136 is separated from the bottom 133 by a distance corresponding to substantially one quarter of the wavelength of the sound to be absorbed by the sound absorbing material. The opening is formed to be smaller than the wavelength. The sound absorbing device 130 has a cylindrical shape as a whole and extends in a direction perpendicular to the paper surface of FIG.
The cells 134 are separated by the peripheral portion 132 not only in the circumferential direction of FIG. 9A but also in the direction perpendicular to the paper surface. The peripheral portion 132 has a triangular cross section, and the opening is a pointed end.

The sound absorbing device 140 shown in FIG. 21 in a sectional state.
The plate member is disposed on the peripheral portion 142 and the bottom portion 143, and includes a plurality of cells 144 formed with the top portion as an opening, and a sound absorbing material 146 disposed in the opening of each cell. The sound absorbing material 146 is separated from the bottom portion 143 by a distance corresponding to substantially one quarter of the wavelength of the sound to be absorbed by the sound absorbing material. The opening is formed to be smaller than the wavelength. The sound absorbing device 140 has a cylindrical shape as a whole and extends in a direction perpendicular to the paper surface of FIG.
The cells 144 are divided by the peripheral portion 142 not only in the circumferential direction of FIG. 9A but also in the direction perpendicular to the paper surface. The peripheral portion 142 has a substantially elliptical cross section. In the sound absorbing device of FIGS. 20 and 21, since the cell opening is large, sound easily enters the sound absorbing device.

The sound absorbing device 150 shown in FIG. 22 in a sectional state.
Includes a plurality of cells 154 each having a plate material arranged in the peripheral portion 152 and having openings at the top and bottom thereof, and a sound absorbing material 156 arranged in each of the openings of each cell. The sound absorbing material 156 at the top and the sound absorbing material 156 at the bottom are separated by a distance corresponding to substantially one half of the wavelength of the sound to be absorbed by these sound absorbing materials, and the opening is smaller than the wavelength. Is formed. The cell 154 is shown in FIG.
Like the cell 102 of the sound absorbing device 100 shown in FIG. In this form, the sound wave that has passed through one of the sound absorbing materials becomes a vibration in which the two sound absorbing materials 156 are antinodes. Therefore, by setting the distance between the two sound absorbing materials 156 to the above-mentioned distance, Energy of particle velocity can be effectively absorbed.

The sound absorbing device 160 shown in FIG. 23 in a sectional state.
Is a plurality of cells 1 formed by arranging plate members on the peripheral portion 162 and the bottom portion 163 and arranging a plate member 164 having an opening at the top so that the cross-sectional shape is substantially circular.
66 and a sound absorbing material 168 arranged in the opening of each cell. The cell 166 has a partition member 167 that hangs from the plate member 168 in the vicinity of the opening of the plate member 168 and extends from the peripheral portion 162 to the center in the radial direction, and the sound entered from the opening propagates in the circumferential direction. It is formed so as to be reflected by the partition member 167 and return to the opening. The opening of the cell 166 and the partition member 167 are separated from each other by a distance corresponding to substantially a quarter of the wavelength of the sound to be absorbed by the sound absorbing material 168 so that the opening is smaller than the wavelength. Has been formed. In this aspect, the sound absorbing device 160 is formed in a cylindrical shape as a whole. Since the cell 166 has a circular cross-sectional shape and the bottom portion 163 is located at the center of the circle, the length in the circumferential direction at the midpoint of the distance from the bottom portion 163 to the peripheral portion 162 becomes ¼ of the wavelength. Can be specified.

The sound absorbing device 100 shown in FIG. 16 is shown in FIG.
You can place it like this and use it. In the figure (a), the sound absorbing device 100 is provided in the engine room 1 at each side of the engine 170.
The sound absorbing member 104 is horizontally arranged in the position 72, and is positioned so as to face the road surface 174. In the same figure (b), the sound absorbing device 100 is provided on each side of the engine 170 in the engine room 1.
72 is obliquely arranged, and the sound absorbing material 104 is disposed in the engine 17
0 and the road surface 174 are inclined and face each other. In the same figure (c), the sound absorbing device 100 has an engine 170
Placed vertically in the engine room 172 on each side of
The sound absorbing material 104 is located so as to face the engine 170.

The cylindrical sound absorbing devices 130, 140 and 160 can be arranged in the same manner as in FIG. In this case, the sound absorbing device can be arranged such that its axis is in the front-rear direction of the vehicle body, the width direction of the vehicle body, or the vertical direction, and a plurality of such sound absorbing devices can be arranged in the front-rear direction. When the axis is arranged in the front-rear direction or the width direction of the vehicle body, it can be arranged in a plurality of rows in the vertical direction or the vertical direction.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing the principle of a sound absorbing device according to the present invention.

FIG. 2 is a cross-sectional view schematically showing another principle of the sound absorbing device according to the present invention.

FIG. 3 is a sectional view of an embodiment of the sound absorbing device according to the present invention.

4 is a perspective view of the sound absorbing device shown in FIG.

FIG. 5 is a sectional view showing another embodiment of the sound absorbing device according to the present invention.

FIG. 6 is a perspective view showing still another embodiment of the sound absorbing device according to the present invention.

FIG. 7 is a front view showing an arrangement example of a sound absorbing device.

FIG. 8 is a bottom view of the arrangement example shown in FIG. 7, which is shown in a reduced scale.

FIG. 9 is a front view showing another arrangement example of the sound absorbing device.

FIG. 10 is a front view showing still another arrangement example of the sound absorbing device.

FIG. 11 is a front view showing still another arrangement example of the sound absorbing device.

FIG. 12 is a front view showing still another arrangement example of the sound absorbing device.

FIG. 13 is a front view showing still another arrangement example of the sound absorbing device.

FIG. 14 is a front view showing still another arrangement example of the sound absorbing device.

FIG. 15 is a front view showing still another arrangement example of the sound absorbing device.

FIG. 16 is a perspective view showing still another embodiment of the sound absorbing device according to the present invention.

17 is a cross-sectional view of the sound absorbing device shown in FIG.

FIG. 18 is a cross-sectional view showing another example of the opening and the sound absorbing material of the sound absorbing device shown in FIG. 16, and (a) to (c) show different modes.

FIG. 19 is a cross-sectional view showing a modified example of the sound absorbing device shown in FIG.

FIG. 20 is a cross-sectional view showing yet another embodiment of the sound absorbing device according to the present invention, (a) is a linearly expanded and enlarged view, and (b) is a cross-sectional view taken along a line orthogonal to the axis. is there.

FIG. 21 is a cross-sectional view showing still another embodiment of the sound absorbing device according to the present invention, (a) is a linearly expanded view and (b) is a cross section taken along a plane orthogonal to the axis. is there.

FIG. 22 is a sectional view showing still another embodiment of the sound absorbing device according to the present invention.

FIG. 23 is a cross-sectional view showing still another embodiment of the sound absorbing device according to the present invention, (a) being cut along the axis,
(B) is cut along a plane perpendicular to the axis.

FIG. 24 is a front view showing another arrangement example of the sound absorbing device,
) To (c) show different embodiments.

[Explanation of symbols]

40, 40A, 60, 60A, 70, 100, 130,
140 sound absorbing device 150, 160 sound absorbing device 44, 64, 74 air layer 46, 46A, 66, 76, 104, 110, 120,
136 sound absorbing material 146, 156, 162 sound absorbing material 102, 108, 116, 134, 144, 154, 1
66 cells 106, 132, 142, 152, 162 peripheral parts 107, 109, 119, 133, 143, 163 bottom parts

Claims (6)

(57) [Claims] 1. A substrate formed of a plate material having a substantially rectangular planar shape and having four sides, and a substrate disposed over two opposing sides of the substrate, with an air layer interposed on at least one side of the substrate. The sound absorbing material is located in a curved shape that is gradually curved away from the substrate from each of the two sides toward the center between the two sides. The sound absorbing material extends between the remaining two sides, and the sound absorbing material is located at a position farthest from the substrate.
The center of the thickness of the sound absorbing material is from the surface of the substrate,
A sound absorbing device, which is dimensioned to have a distance of 1/4 of a wavelength of sound to be absorbed by the sound absorbing material. 2. A substrate made of a plate material having a substantially rectangular planar shape and having four sides, and arranged from one of two opposing sides of the substrate to above or below the other side. A sound absorbing material located on at least one side of the substrate with an air layer interposed, and the sound absorbing material is curved so as to gradually separate from the substrate as one of the two sides faces the other side. The curved shape is formed, and the curved shape extends between the remaining two sides, and the sound absorbing material is formed on the substrate on the side of the other side.
The sound absorbing device is dimensioned such that the distance from the surface of the sound absorbing material to the center of the thickness of the sound absorbing material is ¼ of the wavelength of the sound to be absorbed by the sound absorbing material. 3. A substrate made of a plate material, and a sound absorbing material that is raised from the peripheral edge of the substrate and is located on at least one side of the substrate with an air layer interposed therebetween. The sound absorbing material faces the center from the peripheral edge. The distance from the substrate to the center of the thickness of the sound absorbing material at the portion farthest from the substrate is 1/4 of the wavelength of the sound to be absorbed by the sound absorbing material. Sound absorbing device that is dimensioned to 4. A plate material is arranged at a peripheral portion and a bottom portion, and a plurality of cells each having a top portion formed as an opening and a sound absorbing material arranged at the opening of each cell are provided. A sound absorbing device, formed by a distance from the bottom substantially equal to one quarter of the wavelength of the sound to be absorbed by the opening, the opening being smaller than the wavelength. 5. A sound absorbing material at the top, and a plurality of cells each having a plate material arranged around the periphery and having openings at the top and bottom, and a sound absorbing material arranged at each of the openings of each cell. The sound absorbing material at the bottom is separated by a distance corresponding to substantially one-half the wavelength of the sound to be absorbed by these sound absorbing materials, and the opening is formed to be smaller than the wavelength. apparatus. 6. A cell formed by arranging plate members at a peripheral portion and a bottom portion and arranging a plate member having an opening at a top portion so as to have a substantially circular cross-sectional shape, the opening at the top portion. Has a partition member that hangs from the top in the vicinity of and that extends from the peripheral portion to the center in the radial direction, and the sound entered from the opening propagates in the circumferential direction and is reflected by the partition member, and the opening A plurality of cells formed so as to return to, and a sound absorbing material arranged in the opening of each cell, the opening of the cell and the partitioning material, of the wavelength of the sound to be absorbed by the sound absorbing material. A sound absorbing device, wherein the openings are formed so as to be separated from each other by a distance substantially corresponding to a quarter and the opening is smaller than the wavelength.