JP2011113057A - Sound insulating material, sound insulation system, and method of manufacturing the sound insulating material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound insulating material for improving the sound insulation. <P>SOLUTION: The sound insulating material 10 includes: a sound insulation plate 20 continuing over the whole surface; a sound source-side hole-opening plate 30 that is arranged on a side closer to a sound source 2 than to the sound insulation plate 20 and has a plurality of through-holes 31 for sound absorption; and a radiation-side hole-opening plate 40 that is arranged on a side opposite to the sound source 2 with respect to the sound insulation plate 20 and has a plurality of through-holes 41 for radiation sound reduction. The sound insulation plate 20 has a shape reciprocating between both hole-opening plates 30 and 40 so as to alternately have a plurality of sound source-side joints 21 and a plurality of radiation-side joints 22 joined to both hole opening plates 30 and 40, respectively, while forming a sound source-side air layer 50 and radiation-side air layer 60 between the sound insulation plate 20 and the sound source-side hole-opening plate 30 and radiation-side hole-opening plate 40, respectively. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a soundproof material, a soundproof system, and a method of manufacturing a soundproof material.

  Conventionally, a soundproofing material for absorbing sound emitted from a sound source is known (for example, Patent Document 1).

  Such a sound insulating material includes a sound insulating plate that is continuous over the entire surface, and a perforated plate that is disposed closer to the sound source than the sound insulating plate and has a plurality of through holes. An air layer is formed between the sound insulating plate and the perforated plate.

  In the above soundproofing material, sound from the sound source is absorbed by the perforated plate and the air layer to make soundproofing.

JP 2000-190744 A

  However, with the above conventional soundproofing material, it is possible to absorb sound, but when the sound insulation plate vibrates with sound from the sound source, radiated sound is generated from the sound insulation plate, and this radiated sound is opposite to the sound source. There was a problem of being transmitted to the side (radiation side).

  The present invention has been made to solve the above-described problems, and manufacture of a soundproofing material, a soundproofing system, and a soundproofing material capable of improving the soundproofing performance by suppressing the transmission of radiated sound from the sound insulating plate. It aims to provide a method.

  In order to achieve the above object, a soundproofing material according to claim 1 of the present invention is a soundproofing material for absorbing and blocking sound emitted from a sound source, the sound insulating plate continuous over the entire surface, and the sound insulating material A sound source side perforated plate having a plurality of sound absorbing through holes disposed on a side closer to the sound source than the plate, and a sound wave reducing plate disposed on the opposite side of the sound source with the sound insulating plate interposed therebetween. A sound source side air layer and a radiation side air layer between the sound source side hole plate and the radiation side hole plate, respectively. However, it has a shape that reciprocates between the two perforated plates so as to alternately have a plurality of sound source side joint portions and a plurality of radiation side joint portions respectively joined to the two perforated plates.

  According to the soundproofing material of claim 1, in addition to the sound absorbing effect of suppressing the reflection of the sound from the sound source to the sound source side, the transmission of the sound from the sound source to the opposite side (radiation side) of the sound source is suppressed. Sound insulation effect can be obtained sufficiently. That is, in this soundproofing material, a sound source side air layer and a radiation side air layer are formed between the sound insulating plate and each perforated plate, respectively, by arranging perforated plates on the sound source side and the radiation side of the sound insulating plate. Configured. Thereby, the sound absorption effect is obtained by the sound source side perforated plate and the sound source side air layer. Specifically, sound is absorbed by losing energy due to friction with the sound source side perforated plate when sound from the sound source passes through the sound absorbing through hole of the sound source side perforated plate. Furthermore, the radiation-side perforated plate and the radiation-side air layer suppress the transmission of the radiated sound generated due to the vibration of the sound-insulating plate due to the sound from the sound source, thereby obtaining a further sound-insulating effect. The principle of this radiated sound suppression is the same as the principle of sound absorption described above. Lose energy. Thus, sound absorption and sound insulation are sufficiently exhibited, and an excellent soundproofing effect can be obtained.

  Further, the sound source side air layer and the radiation side air layer can also be formed by arranging flat plate perforated plates in parallel on the front and back of a flat plateless hole plate, for example. Spacers and a heavy support frame are required to maintain the temperature. On the other hand, in the present invention, since the sound insulating plate has a shape that reciprocates between the two perforated plates, the sound insulating plate is formed between each perforated plate only by joining the sound insulating plate to each perforated plate. The shape of the air layer can be easily maintained. Further, in this case, since a separate joining member for joining the sound insulating plate and each perforated plate is not required, the configuration of the soundproof material is simplified.

  The soundproof material according to claim 2 is the soundproof material according to claim 1, wherein the sound source side perforated plate and the radiation side perforated plate have the same plate thickness and opening shape, and the sound source side. Compared to the case where the volume of the air layer and the radiation side air layer are the same, the frequency at which the sound absorption coefficient in the sound source side air layer is maximized and the frequency at which the amount of radiation sound reduction in the radiation side air layer is maximized. The thickness and opening shape of each of the perforated plates and the volume of each of the air layers are set so as to reduce the difference.

  If each parameter is set in this way so that the difference between two peak frequencies (maximum frequency) is reduced, for example, for a sound source that emits a sound having a sharp peak at a specific frequency, By setting a frequency range in which both the sound absorption rate and the amount of radiated sound reduction are increased with the frequency as a target, high soundproofing can be obtained.

  The soundproofing material according to claim 3 is the soundproofing material according to claim 2, wherein the sound source side perforated plate and the radiation side perforated plate have a flat plate shape having the same thickness and opening shape. The sound insulation plates are arranged in parallel with each other, and the sound insulation plate has a shape that makes the volume of the sound source side air layer smaller than the volume of the radiation side air layer.

  If the shape of the sound insulating plate is set so that the volume of the sound source side air layer is smaller than the volume of the radiation side air layer, the difference between the peak frequency of the sound absorption coefficient and the peak frequency of the radiated sound reduction amount is reduced. Thus, even when two perforated plates having the same thickness and opening shape are used, the difference between the two peak frequencies can be reduced by devising the shape of the sound insulating plate. As much as can be used, the configuration is simplified and the cost is reduced.

  In the two perforated plates, the same opening shape means that the shape and arrangement of each through hole are the same.

  The soundproof material according to claim 4 is the soundproof material according to claim 3, wherein portions of the sound insulating plate interposed between the sound source side joints and the radiation side joints are the sound sources. It has the shape which becomes convex at the side air layer side.

  In this way, the sound insulating plate is formed in a shape that protrudes toward the sound source side air layer side with the portion interposed between the respective joints, compared to the case where the interposed portion has a planar shape, compared to the sound source side. As the volume of the air layer decreases, the volume of the radiation side air layer increases. Therefore, the volume of the sound source side air layer can be easily made smaller than the volume of the radiation side air layer, and the difference between the two peak frequencies can be easily reduced.

  According to a fifth aspect of the present invention, there is provided a soundproofing system comprising: a motor as a sound source; and a soundproofing material disposed so as to face the motor and absorbing and blocking sound emitted from the motor. A soundproofing system comprising the soundproofing material according to any one of claims 2 to 4 as the soundproofing material, wherein the soundproofing material has a sound source side perforated plate positioned closer to the motor than the soundproofing plate. It is arranged by these.

  According to the soundproofing system of the fifth aspect, high soundproofing can be obtained for a motor that emits a sound having a sharp peak at a specific frequency.

  The soundproof material according to claim 6 is the soundproof material according to claim 1, wherein the sound source side perforated plate and the radiation side perforated plate have the same plate thickness and opening shape, and the sound source side. Compared to the case where the volume of the air layer and the radiation side air layer are the same, the frequency at which the sound absorption coefficient in the sound source side air layer is maximized and the frequency at which the amount of radiation sound reduction in the radiation side air layer is maximized. The plate thickness and opening shape of each perforated plate and the volume of each air layer are set so as to widen the difference.

  If each parameter is set in this way so that the difference between the two peak frequencies (maximum frequency) increases, the frequency range in which at least one of the sound absorption rate and the amount of radiated sound reduction increases can be expanded. Can do. Therefore, for example, sufficient soundproofing can be obtained for a sound source that requires soundproofing over a wide frequency range.

  The soundproof material according to claim 7 is the soundproof material according to claim 6, wherein the sound source side perforated plate and the radiation side perforated plate have a flat plate shape having the same plate thickness and opening shape. The sound insulating plates are arranged in parallel to each other, and the sound insulating plate has a shape that makes the volume of the radiation side air layer smaller than the volume of the sound source side air layer.

  If the shape of the sound insulating plate is set so that the volume of the radiation-side air layer is smaller than the volume of the sound source-side air layer, the difference between the peak frequency of the sound absorption coefficient and the peak frequency of the radiated sound reduction amount increases. In this way, even when two perforated plates having the same thickness and opening shape are used, the difference between the two peak frequencies can be increased by devising the shape of the sound insulating plate. As much as can be used, the configuration is simplified and the cost is reduced.

  The soundproof material according to claim 8 is the soundproof material according to claim 7, wherein portions of the sound insulating plate interposed between the sound source side joints and the radiation side joints are the radiations. It has the shape which becomes convex at the side air layer side.

  In this way, the sound insulating plate is formed in a shape in which the portion interposed between the respective joints is convex to the radiation side air layer side, and compared to the case where the interposed portion has a planar shape, the radiation side. As the volume of the air layer decreases, the volume of the sound source side air layer increases. Therefore, the volume of the radiation side air layer can be easily made smaller than the volume of the sound source side air layer, and the difference between the two peak frequencies can be easily expanded.

  According to a ninth aspect of the present invention, there is provided a soundproofing system that absorbs and blocks a muffler that is a sound source provided on the exhaust side of an engine and a muffler that is disposed so as to face the muffler. A soundproofing system comprising: a soundproofing system according to any one of claims 6 to 8, wherein the soundproofing material has a sound source side perforated plate from the soundproofing plate. Is also arranged in a posture positioned on the muffler side.

  According to the soundproofing system of the ninth aspect, sufficient soundproofing can be obtained for a muffler that requires soundproofing over a wide frequency range.

  The method for manufacturing a soundproof material according to claim 10 of the present invention is a method for manufacturing a soundproof material for absorbing and blocking sound emitted from a sound source, and has the same plate thickness and opening shape. A sound source side perforated plate and a radiation side perforated plate, and a sound source between the sound source side perforated plate and the radiation side perforated plate by pressing a continuous metal plate over the entire surface. Forming a sound insulating plate having a shape having alternately a plurality of sound source side joint portions and a plurality of radiation side joint portions that can be respectively joined to the two perforated plates while forming a side air layer and a radiation side air layer And joining the sound source side perforated plate to each sound source side joint of the sound insulation plate and joining the radiation side sound insulation plate to each radiation side joint of the sound insulation plate. And

  According to the method for manufacturing a soundproof material according to claim 10, since the soundproof material is manufactured by bonding each joint portion of the soundproof plate formed by pressing to each perforated plate, A joining member for joining the perforated plate is not required separately. Thereby, the manufacturing process of the soundproofing material is simplified to the extent that the process of manufacturing the joining member can be omitted.

  In addition, the volume ratio between the two air layers can be easily changed by simply forming the part interposed between the two joints of the sound insulating plate during the pressing process into a shape that protrudes toward one of the air layers, for example. Therefore, the difference between the frequency at which the sound absorption coefficient in the sound source side air layer becomes the maximum and the frequency at which the amount of radiation sound reduction in the radiation side air layer becomes the maximum can be easily reduced or expanded.

  According to the soundproofing material of the present invention, sound absorption and sound insulation are sufficiently exhibited, and an excellent soundproofing effect can be obtained.

It is sectional drawing which showed the structure of the soundproof system by 1st Embodiment of this invention. It is the graph which showed each relationship between the frequency when the volume of a sound source side air layer and the volume of a radiation side air layer are equal, a sound absorption factor, and a radiation sound reduction amount. It is the graph which showed each relationship of volume ratio, peak frequency ratio, and reverse peak frequency ratio. It is sectional drawing which showed the structure of the soundproof system by 2nd Embodiment. It is the graph which showed each relationship between the frequency when the volume of a sound source side air layer is smaller than the volume of a radiation side air layer, a sound absorption rate, and a radiation sound reduction amount. It is sectional drawing which showed the structure of the soundproofing system by the modification of 2nd Embodiment. It is sectional drawing which showed the structure of the soundproofing system in case a sound source is a motor. It is sectional drawing which showed the structure of the soundproof system by 3rd Embodiment. It is the graph which showed each relationship between the frequency in case the volume of a sound source side air layer is larger than the volume of a radiation side air layer, a sound absorption factor, and a radiated sound reduction amount. It is sectional drawing which showed the structure of the soundproofing system in case a sound source is a muffler.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
As shown in FIG. 1, the soundproof system 1 of the first embodiment includes a sound source 2 and a soundproof material 10 disposed so as to face the sound source 2.

  The soundproofing material 10 has a soundproofing function for absorbing and blocking sound emitted from the sound source 2. The sound insulating material 10 is a sound insulating plate 20 that is continuous over the entire surface, a sound source side perforated plate 30 that is disposed closer to the sound source 2 than the sound insulating plate 20 and has a plurality of sound absorbing through holes 31, and the sound insulating plate 20. And a radiation-side perforated plate 40 having a plurality of through holes 41 for reducing radiation sound.

  The perforated plates 30 and 40 are formed in a flat plate shape having the same thickness and opening shape, and are arranged in parallel postures. Here, the same opening shape means that the shapes and arrangements of the through holes 31 and 41 are the same. In addition, as a shape of the through-holes 31 and 41, a round hole, a square hole, etc. are mentioned. In addition, examples of the arrangement pattern of the through holes 31 include regular patterns such as a staggered pattern and a parallel pattern.

  The sound insulating plate 20 has a wave shape reciprocating between the two perforated plates 30 and 40, and is joined to the perforated plates 30 and 40, respectively. Such a sound insulating plate 20 is formed, for example, by pressing a metal plate.

  A plurality of sound source side air layers 50 are formed between the sound insulating plate 20 and the sound source side perforated plate 30. A plurality of radiation side air layers 60 are formed between the sound insulating plate 20 and the radiation side perforated plate 40.

  For example, the sound source side air layer and the radiation side air layer can also be formed by arranging the flat perforated plates in parallel on the front and back of the flat plate without holes. A spacer to maintain it and a heavy support frame are required. On the other hand, in this embodiment, since the sound insulating plate 20 is shaped to reciprocate between the two perforated plates 30 and 40, only by joining the sound insulating plate 20 to the perforated plates 30 and 40, respectively. The shape of the air layers 50 and 60 formed between the perforated plates 30 and 40 can be easily maintained. Moreover, in this case, since the joining member for joining the sound insulation board 20 and each perforated board 30 and 40 is not required separately, the structure of the said soundproofing material 10 becomes simple.

  Specifically, the sound insulating plate 20 alternately includes a plurality of sound source side joints 21 joined to the sound source side perforated plate 30 and a plurality of radiation side joints 22 joined to the radiation side perforated plate 40. And a plurality of connecting walls 23 and 24 for connecting adjacent joints 21 and 22.

  The joining portion 21 is a folded portion on one side of the sound insulating plate 20 (the folded portion on the valley side in FIG. 1), extends in a specific direction (a direction orthogonal to the paper surface in FIG. 1), and the specific direction. They are provided at a predetermined pitch in the orthogonal direction.

  The joint portion 22 is a folded portion on the other side of the sound insulating plate 20 (the folded portion on the mountain side in FIG. 1), extends in the same specific direction as the joint portion 21, and joins in a direction orthogonal to the specific direction. 21 at the same pitch.

  These joint portions 21 and 22 are formed in a shape (width) in which the joint area becomes as small as possible within a range in which the joint strength between the sound insulating plate 20 and the perforated plates 30 and 40 can be secured. Thereby, the fall of a sound absorption property and sound insulation is suppressed.

  The connection wall 23 connects one end (the right end in the drawing) of the sound source side joining portion 21 and the other end (the left end in the drawing) of the radiation side joining portion 22 and is formed in a flat plate shape. The connecting walls 23 are arranged in a posture that is parallel to each other.

  The connecting wall 24 connects the other end (the left end in the figure) of the sound source side joining portion 21 and one end (the right end in the drawing) of the radiation side joining portion 22 and is formed in a flat plate shape. The connecting walls 24 are arranged in a posture that is parallel to each other.

  Further, the angle θ1 formed by the connecting wall 23 and the sound source side perforated plate 30 is equal to the angle θ2 formed by the connecting wall 24 and the sound source side perforated plate 30.

  Each of the sound source side air layers 50 is a space surrounded by the adjacent connection walls 23 and 24 and the sound source side perforated plate 30, and each of the radiation side air layers 60 is formed of the adjacent connection walls 23 and 24 and the radiation side. It is a space surrounded by the perforated plate 40. In the soundproofing material 10 of the first embodiment, the volume of the sound source side air layer 50 and the volume of the radiation side air layer 60 are equal to each other.

  Such a soundproofing material 10 is manufactured by joining the respective joint portions 21 and 22 of the sound insulating plate 20 formed by pressing to two perforated plates 30 and 40 having the same thickness and opening shape. Is done. According to this manufacturing method, since a separate joining member for joining the sound insulating plate 20 and the perforated plates 30 and 40 is not required, the process is simplified to the extent that the process of producing the joining member can be omitted. Become.

  In the soundproofing material 10 of the first embodiment, in addition to the sound absorption effect that suppresses the reflection of the sound from the sound source 2 to the sound source side, the sound from the sound source 2 is transmitted to the side opposite to the sound source 2 (radiation side). Sufficient sound insulation effect can be obtained.

  That is, in the soundproofing material 10, the sound source side perforated plate 30 and the radiation side perforated plate 40 are arranged on the sound source side and the radiation side of the sound insulating plate 20, respectively. The sound source side air layer 50 and the radiation side air layer 60 are formed respectively.

  Thereby, the sound absorption effect is obtained by the sound source side perforated plate 30 and the sound source side air layer 50. Specifically, sound is absorbed by losing energy due to friction with the sound source side perforated plate 30 when the sound from the sound source 2 passes through the sound absorbing through hole 31 of the sound source side perforated plate 30. Further, the radiation side perforated plate 40 and the radiation side air layer 60 suppress the transmission of the radiated sound generated due to the vibration of the sound insulation plate 20 due to the sound from the sound source 2, thereby further improving the sound insulation effect. can get. The principle of the radiated sound suppression is the same as the principle of the sound absorption described above, and the radiated sound generated by the sound insulating plate 20 passes through the radiated sound reducing through hole 41 of the radiant side perforated plate 40. Loss energy by friction with 40. Thus, sound absorption and sound insulation are sufficiently exhibited, and an excellent soundproofing effect can be obtained.

  By the way, the soundproofing material 10 of the first embodiment, that is, the sound source side perforated plate 20 and the radiation side perforated plate 30 have the same plate thickness and opening shape, and the sound source side air layer 50 and the radiation side air layer 60 are formed. Specifically, the soundproofing material 10 having the same volume has sound absorption characteristics and radiation sound reduction characteristics as shown in FIG. According to this, the sound absorption rate and the amount of radiated sound reduction by the soundproofing material 10 vary depending on the frequency. In the case of the soundproofing material 10 of the first embodiment, the frequency at which the sound absorption rate is maximized (the peak frequency of the sound absorption rate) p1 is greater than the frequency at which the amount of radiated sound reduction is maximized (the peak frequency of the radiated sound reduction amount) p2. The frequency is smaller and the frequency at which the radiated sound reduction amount is minimized (the reverse peak frequency of the radiated sound reduction amount) is greater than p3.

  In addition, there is a difference between the ratio of the volume of the radiation-side air layer to the volume of the sound-source-side air layer (volume ratio) and the ratio of the peak frequency of the radiation sound reduction amount to the peak frequency of the sound absorption coefficient (peak frequency ratio). There is a correlation as shown in FIG. According to this, when the volume ratio varies, the peak frequency ratio also varies. Further, the ratio of the reverse peak frequency of the radiated sound reduction amount to the peak frequency of the sound absorption coefficient (reverse peak frequency ratio) also varies according to the variation of the volume ratio.

  The inventor of the present application pays attention to them and has come up with the idea that the difference between the peak frequencies p1 and p2 (p3) can be adjusted by changing the volume ratio of the air layers 50 and 60 to change the peak frequency ratio.

  When the soundproof material is configured so that the volume of the sound source side air layer is smaller than the volume of the radiation side air layer, that is, the volume ratio is greater than 1, the volume of each air layer is equal ( It has been found that the soundproofing material can be provided with a soundproofing characteristic in which the peak frequency ratio is smaller than that in FIG. 2, that is, the difference between the peak frequency of the sound absorption coefficient and the peak frequency of the radiated sound reduction amount is reduced. With the soundproofing material having such soundproofing characteristics, a high soundproofing property can be obtained for a sound source that emits a sound having a sharp peak at a specific frequency.

  Conversely, when the soundproof material is configured so that the volume of the radiation-side air layer is smaller than the volume of the sound source-side air layer, that is, the volume ratio is smaller than 1, the volume of each air layer is equal. It was found that the soundproofing material can be provided with a soundproofing characteristic in which the peak frequency ratio is large, that is, the difference between the peak frequency of the sound absorption coefficient and the peak frequency of the radiated sound reduction amount is increased. With such a soundproofing material having soundproofing characteristics, sufficient soundproofing can be obtained for a sound source that requires soundproofing over a wide frequency range.

  Below, the structure of the soundproof system of the form different from 1st Embodiment provided with the soundproof material which has said each soundproof characteristic is each demonstrated.

(Second Embodiment)
The soundproofing material of the soundproofing system according to the second embodiment is configured to exhibit high soundproofing properties for a sound source that emits a sound having a sharp peak at a specific frequency, such as a motor. In this soundproof material, the volume ratio of the air layer is larger than 1, that is, the volume of the sound source side air layer is smaller than the volume of the radiation side air layer.

  Specifically, as shown in FIG. 4, the soundproofing material 110 of this soundproofing system includes a sound insulating plate 120 having a configuration different from that of the sound insulating plate 20 of the first embodiment.

  The sound insulating plate 120 has a plurality of connecting walls 123 and 124 that connect adjacent joints 21 and 22.

  The connection wall 123 connects one end (the right end in the figure) of the sound source side joint 21 and the other end (the left end in the figure) of the radiation side joint 22, and the sound source side air layer 150 side (the lower side in the figure). It is formed in a shape bent so as to be convex.

  The connection wall 124 connects the other end (left end in the figure) of the sound source side joint 21 and one end (right end in the figure) of the radiation side joint 22, and the sound source side air layer 150 side (lower side in the figure). It is formed in a shape bent so as to be convex.

  As described above, since the sound insulating plate 120 is formed in a shape in which the connecting walls 123 and 124 interposed between the joints 21 and 22 are bent so as to protrude toward the sound source side air layer side, the connecting wall Compared to the case where the (intervening portion) has a planar shape, the volume of the sound source side air layer 150 is reduced and the volume of the radiation side air layer 160 is increased. Therefore, the volume of the sound source side air layer 150 is smaller than the volume of the radiation side air layer 160 and the volume ratio is larger than 1. Thereby, compared with the case where the volume of each air layer is equal, a peak frequency ratio becomes small, and the difference of two peak frequency p1, p2 reduces. This makes it possible to set a frequency range in which both the sound absorption rate and the amount of radiated sound reduction are large. For example, for a sound source that emits a sound having a sharp peak at a specific frequency, the frequency that becomes the peak is set. High soundproofing can be obtained by setting a frequency range in which both the sound absorption coefficient and the amount of radiated sound reduction are large as targets.

  In particular, as shown in FIG. 5, when the shape of the sound insulating plate 120 is set so that the volume ratio is such that the peak frequency p1 of the sound absorption coefficient and the peak frequency p2 of the radiated sound reduction amount coincide with each other, A particularly high soundproofing effect can be obtained for a sound source that emits a sound having a sharp peak in frequency.

  Further, in the soundproofing material 110 of the second embodiment, the same thickness can be obtained by devising the shape of the sound insulating plate 120, that is, by forming the connecting walls 123 and 124 in a shape protruding toward the sound source side air layer. Even when two perforated plates 30 and 40 having an opening shape are used, the difference between the two peak frequencies is made small. As a result, the configuration can be simplified and the cost can be reduced because the perforated plates 30 and 40 having the same shape can be used.

  In addition, when the shape of the sound insulating plate 120 is set so that the volume ratio is in the range of about 1.05 to about 2.00, it has a sharp peak at a specific frequency as compared with the case where the volume ratio is 1. The soundproofing effect on the sound source emitting such a sound has been improved by at least about 5%. Furthermore, when the shape of the sound insulating plate 120 is set so that the volume ratio is in the range of about 1.25 to about 1.65, the soundproofing effect on the sound source is at least about compared to the case where the volume ratio is 1. Improved by 30%.

  Further, as a modification of the second embodiment, the soundproofing material 210 including the sound insulating plate 220 shown in FIG. 6 may be used. The connection walls 223 and 224 of the sound insulating plate 220 according to this modification are partially bent and protrude toward the sound source side air layer 250 side. That is, each of the connecting walls 223 and 224 has a rib-like portion 225 having a shape protruding (convex) to the sound source side air layer 250 side (lower side in the drawing). By providing the rib-like portions 225 on the connecting walls 223 and 224 in this way, the rigidity of the sound insulating plate 220 is increased, so that the strength of the sound insulating material 210 is improved.

  Further, when the sound source is a motor, for example, the soundproofing system including the soundproofing material 110 of the second embodiment is configured as shown in FIG. That is, the soundproofing material 110 is arranged in such a posture that the sound source side perforated plate 30 is located closer to the motor 102 than the sound insulating plate 120, thereby having a sharp peak at a specific frequency emitted from the motor 102. Absorbs and blocks sound efficiently.

(Third embodiment)
The soundproofing material of the soundproofing system according to the third embodiment is configured to be able to exhibit sufficient soundproofing properties for a sound source that requires soundproofing over a wide frequency range such as a muffler. In this soundproof material, the volume ratio of the air layer is smaller than 1, that is, the volume of the radiation side air layer is smaller than the volume of the sound source side air layer.

  Specifically, as shown in FIG. 8, the soundproofing material 310 of this soundproofing system includes a sound insulating material 320 having a configuration different from that of the sound insulating plate 20 of the first embodiment.

  The sound insulating plate 320 has a plurality of connecting walls 323 and 324 that connect adjacent joints 21 and 22.

  The connection wall 323 connects one end (right end in the drawing) of the sound source side joining portion 21 and the other end (left end in the drawing) of the radiation side joining portion 22, and is on the radiation side air layer 350 side (upper side in the drawing). It is formed in a bent shape so as to be convex.

  The connection wall 324 connects the other end (left end in the figure) of the sound source side joint 21 and one end (right end in the figure) of the radiation side joint 22, and is on the radiation side air layer 350 side (upper side in the figure). It is formed in a bent shape so as to be convex.

  Thus, since the sound insulating plate 320 is formed in a shape in which the connecting walls 323 and 324 interposed between the joints 21 and 22 are bent so as to protrude toward the radiation side air layer, the connecting wall Compared to the case where the (intervening portion) has a planar shape, the volume of the sound source side air layer 350 is increased and the volume of the radiation side air layer 360 is decreased. Therefore, the volume of the radiation side air layer 360 is smaller than the volume of the sound source side air layer 350 and the volume ratio is smaller than 1. Thereby, compared with the case where the volume of each air layer is equal, the peak frequency ratio is increased, the difference between the two peak frequencies p1 and p2 is increased, and the difference between the peak frequency p1 and the reverse peak frequency p3 is reduced. As a result, it is possible to expand the frequency range in which at least one of the sound absorption rate and the amount of reduction of the radiated sound is increased. For example, sufficient soundproofing can be obtained for a sound source that requires sound insulation over a wide frequency range. It is done.

  In particular, as shown in FIG. 9, when the shape of the sound insulating plate 320 is set so that the volume ratio is such that the peak frequency p1 of the sound absorption coefficient and the reverse peak frequency p3 of the amount of radiated sound reduction match, Since the sound absorption rate is increased and a high sound absorption effect is obtained in a frequency range where the sound reduction amount is small and it is difficult to obtain a sound insulation effect, a sufficiently high sound insulation effect can be obtained over a wide frequency range.

  Further, in the soundproofing material 310 of the third embodiment, the same thickness is obtained by devising the shape of the sound insulating plate 320, that is, by forming the connecting walls 323 and 324 in a shape that protrudes toward the radiation side air layer. Even when two perforated plates 30 and 40 having an opening shape are used, the difference between the two peak frequencies is made large. As a result, the configuration can be simplified and the cost can be reduced because the perforated plates 30 and 40 having the same shape can be used.

  In addition, when the shape of the sound insulating plate 320 is set so that the volume ratio is in the range of about 0.65 to about 0.95, the soundproofing is performed over a wider frequency range than in the case where the volume ratio is 1. The required soundproofing effect for the sound source has been improved by at least about 5%. Furthermore, when the shape of the sound insulating plate 320 is set so that the volume ratio is in the range of about 0.75 to about 0.85, the soundproofing effect on the sound source is at least about compared to the case where the volume ratio is 1. Improved by 15%.

  Also in the third embodiment, it is possible to adopt the configuration of the sound insulating plate 220 (see FIG. 6) having the rib-like portion 225 according to the modification of the second embodiment.

  When the sound source is a muffler, the soundproofing system including the soundproofing material 310 of the third embodiment is configured as shown in FIG. That is, the soundproofing material 310 is arranged in a posture in which the sound source side perforated plate 30 is positioned on the muffler 302 side with respect to the sound insulating plate 320, and thereby, a plurality of the soundproofing materials 310 are spread over a wide frequency range emitted from the muffler 302. Efficiently absorbs and blocks sound with peaks. In FIG. 10, reference numeral 303 denotes a floor of the vehicle body, and reference numeral 304 denotes a fixture for fixing the soundproof material 310 to the floor 303 of the vehicle body.

  In the second and third embodiments, the thickness and opening shape of the two perforated plates are configured to be the same, and the shape of the connecting wall of the sound insulating plate is devised so that the two air layers Although the peak frequency ratio is changed by changing the volume ratio, it is also possible to change the peak frequency ratio by changing the thickness and opening shape of both perforated plates.

DESCRIPTION OF SYMBOLS 1 Soundproof system 2 Sound source 10,110,210,310 Soundproof material 20,120,220,320 Sound insulation board 21 Sound source side junction part 22 Radiation side junction part 23,24,123,124,223,224,323, 324 Connection wall 30 Sound source side perforated plate 31 Sound absorption through hole 40 Radiation side perforated plate 41 Radiation sound reducing through holes 50, 150, 250, 350 Sound source side air layer 60, 160, 260, 360 Radiation side air layer 102 Motor (sound source )
302 Muffler (sound source)

Claims (10)

A soundproofing material for absorbing and blocking sound emitted from a sound source,
A sound insulation board continuous over the entire surface;
A sound source side perforated plate disposed on the side closer to the sound source than the sound insulating plate, and having a plurality of sound absorbing through holes,
A radiation side perforated plate disposed on the opposite side of the sound source across the sound insulation plate, and having a plurality of radiation sound reducing through holes,
The sound insulating plate has a plurality of sound source side joints that are respectively joined to both the perforated plates while forming a sound source side air layer and a radiation side air layer between the sound source side perforated plate and the radiation side perforated plate, respectively. A soundproofing material having a shape that reciprocates between both perforated plates so as to alternately have a plurality of portions and a plurality of radiation side joints. The soundproof material according to claim 1,
The sound source is compared with the case where the sound source side perforated plate and the radiation side perforated plate have the same thickness and opening shape, and the sound source side air layer and the radiation side air layer have the same volume. In order to reduce the difference between the frequency at which the sound absorption coefficient in the side air layer is maximized and the frequency at which the amount of radiated sound reduction in the radiation side air layer is maximized, the plate thickness and the opening shape of each of the perforated plates and each of the above A soundproofing material characterized in that the volume of the air layer is set. The soundproof material according to claim 2,
The sound source side perforated plate and the radiation side perforated plate have a flat plate shape having the same thickness and opening shape, and are arranged in parallel to each other, and the sound insulating plate has a volume of the sound source side air layer. A soundproof material having a shape that is smaller than the volume of the radiation-side air layer. The soundproof material according to claim 3,
A soundproofing material characterized in that a portion of each of the sound insulating plates interposed between each sound source side joint and each radiation side joint has a convex shape toward the sound source side air layer. A soundproofing system comprising a motor as a sound source and a soundproofing material disposed so as to face the motor and absorbing and blocking sound emitted from the motor,
A soundproof material according to any one of claims 2 to 4 is provided as the soundproof material, and the soundproof material is arranged in a posture in which the sound source side perforated plate is positioned closer to the motor side than the soundproof plate. Soundproof system. The soundproof material according to claim 1,
The sound source is compared with the case where the sound source side perforated plate and the radiation side perforated plate have the same thickness and opening shape, and the sound source side air layer and the radiation side air layer have the same volume. In order to increase the difference between the frequency at which the sound absorption coefficient in the side air layer is maximized and the frequency at which the amount of radiated sound reduction in the radiation side air layer is maximized, the plate thickness and the opening shape of each of the perforated plates and each of the above A soundproofing material characterized in that the volume of the air layer is set. The soundproof material according to claim 6,
The sound source side perforated plate and the radiation side perforated plate are flat plates having the same thickness and opening shape, and are arranged in parallel to each other, and the sound insulating plate has a volume of the radiation side air layer. A soundproofing material having a shape that is smaller than the volume of the sound source side air layer. The soundproof material according to claim 7,
The soundproofing material, wherein a portion of the sound insulating plate interposed between each sound source side joint and each radiation side joint has a shape protruding toward the radiation side air layer. A soundproofing system comprising a muffler as a sound source provided on the exhaust side of the engine, and a soundproofing material disposed so as to face the muffler and absorbing and blocking sound emitted from the muffler,
The soundproofing material according to any one of claims 6 to 8 is provided as the soundproofing material, and the soundproofing material is arranged such that the sound source side perforated plate is positioned closer to the muffler than the sound insulating plate. Soundproof system. A method of manufacturing a soundproofing material for absorbing and blocking sound emitted from a sound source,
A step of manufacturing a sound source side perforated plate and a radiation side perforated plate having the same plate thickness and opening shape, and
By pressing a metal plate that is continuous over the entire surface, a sound source side air layer and a radiation side air layer are formed between the sound source side perforated plate and the radiation side perforated plate, respectively. Forming a sound insulation plate having a shape having alternately a plurality of sound source side joints and a plurality of radiation side joints that can be joined; and
Joining the sound source side perforated plate to each sound source side joint portion of the sound insulation plate, and joining the radiation side sound insulation plate to each radiation side joint portion of the sound insulation plate. A method for producing a soundproofing material.

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