Porous Sound Absorbing Structure

Abstract

A porous sound absorbing structure 10 includes an exterior plate 1 and a closing plate 2 in order to suppress a decrease in sound absorbing performance in a wide frequency band. An interior plate 3 is arranged between the exterior plate 1 and the closing plate 2 , and air layers 4 and 5 are located between the exterior plate 1 and the interior plate 3 and between the interior plate 3 and the closing plate 2 respectively. The exterior plate 1 , the interior plate 3 , and the closing plate 2 are arranged while opposed to each other. Many through holes 1 a and 3 a are made in the exterior plate 1 and the closing plate 2 respectively. In the interior plate 3 , a plate thickness t 2 and a diameter φ 2 and an aperture ratio β 2 are set so as to generate an viscous effect in air passing through the through hole 3 a . The aperture ratio β 1 of the through hole 1 a in the exterior plate 1 is set more than 3% and not more than 50%.

1 . A porous sound absorbing structure in which a first outside member and at least one inside member are arranged while opposed to each other, many through holes being made along a flat plane in the inside member, and a plate thickness of said inside member and a diameter and an aperture ratio of the through hole are set so as to generate an viscous effect in air passing through said through hole, the porous sound absorbing structure characterized in that a second outside member is arranged while opposed to said inside member, said second outside member being located on the side opposite to said first outside member with respect to said inside member, many through holes being made along the flat plane in said second outside member, and the aperture ratio of the through hole in said second outside member is more than 3% and not more than 50%.  
   
   
       2 . A porous sound absorbing structure in which a first outside member and at least one inside member are arranged while opposed to each other, many through holes being made along a flat plane in the inside member, and a plate thickness of said inside member and a diameter and an aperture ratio of the through hole are set so as to generate an viscous effect in air passing through said through hole, the porous sound absorbing structure characterized in that a second outside member is arranged while opposed to said inside member, said second outside member being located on the side opposite to said first outside member with respect to said inside member, many through holes being made along the flat plane in said second outside member, and the diameter of the through hole in said second outside member exceeds 3 mm.  
   
   
       3 . A porous sound absorbing structure in which a first outside member and at least one inside member are arranged while opposed to each other, many through holes being made along a flat plane in the inside member, and a plate thickness of said inside member and a diameter and an aperture ratio of the through hole are set so as to generate an viscous effect in air passing through said through hole, the porous sound absorbing structure characterized in that a second outside member is arranged while opposed to said inside member, said second outside member being located on the side opposite to said first outside member with respect to said inside member, many through holes being made along the flat plane in said second outside member, the aperture ratio of the through hole in said second outside member is more than 3% and not more than 50%, and the diameter of the through hole in said second outside member exceeds 3 mm.  
   
   
       4 . A porous sound absorbing structure which includes: 
 a first outside member;    a second outside member which is arranged while opposed to said first outside member, many through holes being made along a flat plane in said second outside member; and    at least one inside member which is arranged while opposed to said first outside member and said second outside member such that said inside member is located between said first outside member and said second outside member, many through holes being made along the flat plane in said second outside member,    the porous sound absorbing structure characterized in that a plate thickness of said inside member and a diameter and an aperture ratio of the through hole are set so as to generate an viscous effect in air passing through said through hole, and the aperture ratio of the through hole in said second outside member is more than 3% and not more than 50%.    
   
   
       5 . A porous sound absorbing structure which includes: 
 a first outside member;    a second outside member which is arranged while opposed to said first outside member, many through holes being made along a flat plane in said second outside member; and    at least one inside member which is arranged while opposed to said first outside member and said second outside member such that said inside member is located between said first outside member and said second outside member, many through holes being made along the flat plane in said second outside member,    the porous sound absorbing structure characterized in that a plate thickness of said inside member and a diameter and an aperture ratio of the through hole are set so as to generate an viscous effect in air passing through said through hole, and the diameter of the through hole in said second outside member exceeds 3 mm.    
   
   
       6 . A porous sound absorbing structure which includes: 
 a first outside member;    a second outside member which is arranged while opposed to said first outside member, many through holes being made along a flat plane in said second outside member; and    at least one inside member which is arranged while opposed to said first outside member and said second outside member such that said inside member is located between said first outside member and said second outside member, many through holes being made along the flat plane in said second outside member,    the porous sound absorbing structure characterized in that a plate thickness of said inside member and a diameter and an aperture ratio of the through hole are set so as to generate an viscous effect in air passing through said through hole, the aperture ratio of the through hole in said second outside member is more than 3% and not more than 50%, and the diameter of the through hole in said second outside member exceeds 3 mm.    
   
   
       7 . The porous sound absorbing structure as in  claim 1 , characterized in that the aperture ratio of the through hole in said inside member is not more than 3%.  
   
   
       8 . The porous sound absorbing structure as in  claim 1 , characterized in that the diameter of the through hole in said inside member is not more than 3 mm.  
   
   
       9 . The porous sound absorbing structure as in  claim 1 , characterized in that air layers are formed between said first outside member and said inside member and between said inside member and said second outside member respectively, and a sound absorbing material is arranged in at least one of said air layers.  
   
   
       10 . The porous sound absorbing structure as in  claim 1 , characterized in that air layers are formed between said first outside member and said inside member and between said inside member and said second outside member respectively, a sound absorbing material made of a resin of metal thin film is arranged in at least one of said air layers, many through holes being made in said sound absorbing material, the aperture ratio of the through hole of said thin film is not more than 3%, and the diameter of the through hole of said thin film is not more than 3 mm.  
   
   
       11 . The porous sound absorbing structure as in  claim 1 , characterized in that at least one of said second outside member and said inside member is inclined with respect to a horizontal plane.  
   
   
       12 . The porous sound absorbing structure as in  claim 1 , characterized in that a drain hole is made in a lower portion of at least one of said second outside member and said inside member.  
   
   
       13 . The porous sound absorbing structure as in  claim 1 , characterized in that said inside member is made of a water-repellent material containing at least one of silicon and fluorine, or a surface of said inside member is coated with a water-repellent material containing at least one of silicon and fluorine.  
   
   
       14 . The porous sound absorbing structure as in  claim 1 , characterized in that at least one of said first outside member, said second outside member, and said inside member is formed so as to have an irregular shape.  
   
   
       15 . The porous sound absorbing structure as in  claim 2 , characterized in that the aperture ratio of the through hole in said inside member is not more than 3%.  
   
   
       16 . The porous sound absorbing structure as in  claim 3 , characterized in that the aperture ratio of the through hole in said inside member is not more than 3%.  
   
   
       17 . The porous sound absorbing structure as in  claim 4 , characterized in that the aperture ratio of the through hole in said inside member is not more than 3%.  
   
   
       18 . The porous sound absorbing structure as in  claim 5 , characterized in that the aperture ratio of the through hole in said inside member is not more than 3%.  
   
   
       19 . The porous sound absorbing structure as in  claim 6 , characterized in that the aperture ratio of the through hole in said inside member is not more than 3%.  
   
   
       20 . The porous sound absorbing structure as in  claim 2 , characterized in that the diameter of the through hole in said inside member is not more than 3 mm.  
   
   
       21 . The porous sound absorbing structure as in  claim 3 , characterized in that the diameter of the through hole in said inside member is not more than 3 mm.  
   
   
       22 . The porous sound absorbing structure as in  claim 4 , characterized in that the diameter of the through hole in said inside member is not more than 3 mm.  
   
   
       23 . The porous sound absorbing structure as in  claim 5 , characterized in that the diameter of the through hole in said inside member is not more than 3 mm.  
   
   
       24 . The porous sound absorbing structure as in  claim 6 , characterized in that the diameter of the through hole in said inside member is not more than 3 mm.  
   
   
       25 . The porous sound absorbing structure as in  claim 2 , characterized in that air layers are formed between said first outside member and said inside member and between said inside member and said second outside member respectively, and a sound absorbing material is arranged in at least one of said air layers.  
   
   
       26 . The porous sound absorbing structure as in  claim 3 , characterized in that air layers are formed between said first outside member and said inside member and between said inside member and said second outside member respectively, and a sound absorbing material is arranged in at least one of said air layers.  
   
   
       27 . The porous sound absorbing structure as in  claim 4 , characterized in that air layers are formed between said first outside member and said inside member and between said inside member and said second outside member respectively, and a sound absorbing material is arranged in at least one of said air layers.  
   
   
       28 . The porous sound absorbing structure as in  claim 5 , characterized in that air layers are formed between said first outside member and said inside member and between said inside member and said second outside member respectively, and a sound absorbing material is arranged in at least one of said air layers.  
   
   
       29 . The porous sound absorbing structure as in  claim 6 , characterized in that air layers are formed between said first outside member and said inside member and between said inside member and said second outside member respectively, and a sound absorbing material is arranged in at least one of said air layers.  
   
   
       30 . The porous sound absorbing structure as in  claim 2 , characterized in that air layers are formed between said first outside member and said inside member and between said inside member and said second outside member respectively, a sound absorbing material made of a resin of metal thin film is arranged in at least one of said air layers, many through holes being made in said sound absorbing material, the aperture ratio of the through hole of said thin film is not more than 3%, and the diameter of the through hole of said thin film is not more than 3 mm.  
   
   
       31 . The porous sound absorbing structure as in  claim 3 , characterized in that air layers are formed between said first outside member and said inside member and between said inside member and said second outside member respectively, a sound absorbing material made of a resin of metal thin film is arranged in at least one of said air layers, many through holes being made in said sound absorbing material, the aperture ratio of the through hole of said thin film is not more than 3%, and the diameter of the through hole of said thin film is not more than 3 mm.  
   
   
       32 . The porous sound absorbing structure as in  claim 4 , characterized in that air layers are formed between said first outside member and said inside member and between said inside member and said second outside member respectively, a sound absorbing material made of a resin of metal thin film is arranged in at least one of said air layers, many through holes being made in said sound absorbing material, the aperture ratio of the through hole of said thin film is not more than 3%, and the diameter of the through hole of said thin film is not more than 3 mm.  
   
   
       33 . The porous sound absorbing structure as in  claim 5 , characterized in that air layers are formed between said first outside member and said inside member and between said inside member and said second outside member respectively, a sound absorbing material made of a resin of metal thin film is arranged in at least one of said air layers, many through holes being made in said sound absorbing material, the aperture ratio of the through hole of said thin film is not more than 3%, and the diameter of the through hole of said thin film is not more than 3 mm.  
   
   
       34 . The porous sound absorbing structure as in  claim 6 , characterized in that air layers are formed between said first outside member and said inside member and between said inside member and said second outside member respectively, a sound absorbing material made of a resin of metal thin film is arranged in at least one of said air layers, many through holes being made in said sound absorbing material, the aperture ratio of the through hole of said thin film is not more than 3%, and the diameter of the through hole of said thin film is not more than 3 mm.  
   
   
       35 . The porous sound absorbing structure as in  claim 2 , characterized in that at least one of said second outside member and said inside member is inclined with respect to a horizontal plane.  
   
   
       36 . The porous sound absorbing structure as in  claim 3 , characterized in that at least one of said second outside member and said inside member is inclined with respect to a horizontal plane.  
   
   
       37 . The porous sound absorbing structure as in  claim 4 , characterized in that at least one of said second outside member and said inside member is inclined with respect to a horizontal plane.  
   
   
       38 . The porous sound absorbing structure as in  claim 5 , characterized in that at least one of said second outside member and said inside member is inclined with respect to a horizontal plane.  
   
   
       39 . The porous sound absorbing structure as in  claim 6 , characterized in that at least one of said second outside member and said inside member is inclined with respect to a horizontal plane.  
   
   
       40 . The porous sound absorbing structure as in  claim 2 , characterized in that a drain hole is made in a lower portion of at least one of said second outside member and said inside member.  
   
   
       41 . The porous sound absorbing structure as in  claim 3 , characterized in that a drain hole is made in a lower portion of at least one of said second outside member and said inside member.  
   
   
       42 . The porous sound absorbing structure as in  claim 4 , characterized in that a drain hole is made in a lower portion of at least one of said second outside member and said inside member.  
   
   
       43 . The porous sound absorbing structure as in  claim 5 , characterized in that a drain hole is made in a lower portion of at least one of said second outside member and said inside member.  
   
   
       44 . The porous sound absorbing structure as in  claim 6 , characterized in that a drain hole is made in a lower portion of at least one of said second outside member and said inside member.  
   
   
       45 . The porous sound absorbing structure as in  claim 2 , characterized in that said inside member is made of a water-repellent material containing at least one of silicon and fluorine, or a surface of said inside member is coated with a water-repellent material containing at least one of silicon and fluorine.  
   
   
       46 . The porous sound absorbing structure as in  claim 3 , characterized in that said inside member is made of a water-repellent material containing at least one of silicon and fluorine, or a surface of said inside member is coated with a water-repellent material containing at least one of silicon and fluorine.  
   
   
       47 . The porous sound absorbing structure as in  claim 4 , characterized in that said inside member is made of a water-repellent material containing at least one of silicon and fluorine, or a surface of said inside member is coated with a water-repellent material containing at least one of silicon and fluorine.  
   
   
       48 . The porous sound absorbing structure as in  claim 5 , characterized in that said inside member is made of a water-repellent material containing at least one of silicon and fluorine, or a surface of said inside member is coated with a water-repellent material containing at least one of silicon and fluorine.  
   
   
       49 . The porous sound absorbing structure as in  claim 6 , characterized in that said inside member is made of a water-repellent material containing at least one of silicon and fluorine, or a surface of said inside member is coated with a water-repellent material containing at least one of silicon and fluorine.  
   
   
       50 . The porous sound absorbing structure as in  claim 2 , characterized in that at least one of said first outside member, said second outside member, and said inside member is formed so as to have an irregular shape.  
   
   
       51 . The porous sound absorbing structure as in  claim 3 , characterized in that at least one of said first outside member, said second outside member, and said inside member is formed so as to have an irregular shape.  
   
   
       52 . The porous sound absorbing structure as in  claim 4 , characterized in that at least one of said first outside member, said second outside member, and said inside member is formed so as to have an irregular shape.  
   
   
       53 . The porous sound absorbing structure as in  claim 5 , characterized in that at least one of said first outside member, said second outside member, and said inside member is formed so as to have an irregular shape.  
   
   
       54 . The porous sound absorbing structure as in  claim 6 , characterized in that at least one of said first outside member, said second outside member, and said inside member is formed so as to have an irregular shape.