Noise absorbing structure and noise absorbing/insulating structure

Abstract

A noise absorbing structure for effectively absorbing noise in a wide frequency range includes a first noise absorbing portion that is hollow and includes one or more first holes. The structure further includes a second noise absorbing portion that is hollow and includes one or more second holes. The total area of the one or more first holes differs from the total area of the one or more second holes.

1 . A noise absorbing structure for absorbing noise, the structure comprising: 
 a first noise absorbing portion that is hollow and includes one or more first holes; and    a second noise absorbing portion that is hollow and includes one or more second holes,    wherein the one or more first holes has a total area different from that of the one or more second holes.    
   
   
       2 . The noise absorbing structure according to  claim 1 , wherein the one or more first holes include two or more first holes each with the same opening area, and the one or more second holes include two or more second holes each with the same opening area.  
   
   
       3 . The noise absorbing structure according to  claim 1 , wherein each of the first and second noise absorbing portions includes a noise insulating wall for insulating noise.  
   
   
       4 . The noise absorbing structure according to  claim 1 , wherein the first noise absorbing portion and the second noise absorbing portion each include a volume that is the same as one another.  
   
   
       5 . The noise absorbing structure according to  claim 1 , wherein the noise absorbing structure is arranged in a vehicle including interior equipment and a drive train for driving the vehicle, the noise absorbing structure being installed in the interior equipment such that the one or more first and second holes are directed toward the drive train.  
   
   
       6 . The noise absorbing structure according to  claim 5 , wherein the first noise absorbing portion has a first noise absorbing wall including the one or more first holes, the second noise absorbing portion has a second noise absorbing wall including one or more second holes, and the total area of the one or more first hole and the one or more second holes is 0.5 to 15.0% of the area of the first and second noise absorbing walls.  
   
   
       7 . The noise absorbing structure according to  claim 5 , wherein the one or more first holes and the one or more second holes each have a diameter that is ten millimeters or less.  
   
   
       8 . The noise absorbing structure according to  claim 5 , wherein the vehicle interior equipment includes a guide wall for holding the noise absorbing structure, and the noise absorbing structure is held by the guide wall.  
   
   
       9 . The noise absorbing structure according to  claim 5 , wherein the interior equipment includes a plurality of parts assembled with a space defined therebetween, and the noise absorbing structure is arranged as a part next to the space.  
   
   
       10 . The noise absorbing structure according to  claim 5 , wherein the first and second noise absorbing portions constitute a noise absorbing body, and the noise absorbing body is one of a plurality of noise absorbing bodies arranged such that the first and second holes in the noise absorbing bodies are directed in different directions.  
   
   
       11 . A noise absorbing/insulating body for absorbing and insulating noise, the body comprising: 
 a first noise absorbing portion that is hollow and includes a first noise absorbing wall having one or more first holes and a first noise insulating wall for insulating noise facing towards the first noise absorbing wall; and    a second noise absorbing portion that is hollow and includes a second noise absorbing wall having one or more second holes and a second noise insulating wall for insulating noise facing towards the second noise absorbing wall,    wherein the one or more first holes has a total area different from that of the one or more second holes.    
   
   
       12 . A noise absorbing structure for absorbing noise, the structure comprising: 
 a first sub-box that is hollow and includes one or more first holes; and    a second sub-box that is hollow, includes one or more second holes, and has the same shape as the first sub-box,    wherein the one or more first holes has a total area different from that of the one or more second holes.    
   
   
       13 . A noise absorbing structure for absorbing noise, the structure comprising: 
 a first noise absorbing portion that is hollow and includes a first noise absorbing wall having one or more first holes; and    a second noise absorbing portion that is hollow and includes a second noise absorbing wall having one or more second holes,    wherein the first noise absorbing portion and the second noise absorbing portion each have a volume that is different from one another.    
   
   
       14 . The noise absorbing structure according to  claim 13 , wherein: 
 the first noise absorbing portion includes a first opposing wall facing towards the first noise absorbing wall;    the second noise absorbing portion includes a second opposing wall facing towards the second noise absorbing wall; and    at least either a set of the first and second noise absorbing walls or a set of the first and second opposing walls includes a step such that the noise absorbing structure corresponds as a whole to a step-like shape.    
   
   
       15 . The noise absorbing structure according to claims  13 , wherein: 
 the first noise absorbing portion includes a first opposing wall facing towards the first noise absorbing wall; and    the second noise absorbing portion includes a second opposing wall facing towards the second noise absorbing wall,    either one of a set of the first and second noise absorbing walls or a set of the first and second opposing walls includes a part inclined with respect to the other one of the set of the first and second noise absorbing walls or the set of the first and second opposing walls.    
   
   
       16 . The noise absorbing structure according to  claim 13 , wherein the noise absorbing structure is arranged in a vehicle including interior equipment and a drive train for driving the vehicle, the noise absorbing structure being installed in the interior equipment such that the one or more first and second holes are directed toward the drive train.  
   
   
       17 . The noise absorbing structure according to  claim 16 , wherein the total area of the one or more first holes and the one or more second holes is 0.5 to 15.0% of the area of the first and second noise absorbing walls.  
   
   
       18 . The noise absorbing structure according to  claim 16 , wherein the one or more first holes and the one or more second holes each have a diameter that is ten millimeters or less.  
   
   
       19 . The noise absorbing structure according to  claim 16 , wherein the vehicle interior equipment includes a guide wall for holding the noise absorbing structure, and the noise absorbing structure is held by the guide wall.  
   
   
       20 . The noise absorbing structure according to  claim 16 , wherein the interior equipment includes a plurality of parts assembled with a space defined therebetween, and the noise absorbing structure is arranged as a part next to the space.  
   
   
       21 . The noise absorbing structure according to  claim 16 , wherein the first and second noise absorbing portions constitute a noise absorbing body, and the noise absorbing body is one of a plurality of noise absorbing bodies arranged such that the first and second holes in the noise absorbing bodies are directed in different directions.  
   
   
       22 . A noise absorbing/insulating structure for absorbing and insulating noise, the structure comprising: 
 a first noise absorbing portion that is hollow and includes a first noise absorbing wall having one or more first holes and a first noise insulating wall for insulating noise facing towards the first noise absorbing wall; and    a second noise absorbing portion that is hollow and includes a second noise absorbing wall having one or more second holes and a second noise insulating wall for insulating noise facing towards the second noise absorbing wall,    wherein the first noise absorbing portion and the second noise absorbing portion each include a volume that is different from one another.    
   
   
       23 . A noise absorbing structure for absorbing noise, the structure comprising: 
 a first sub-box that is hollow and includes one or more first holes; and    a second sub-box that is hollow and includes one or more second holes having the same shape as the first holes,    wherein the one or more first holes has a total area and the one or more second holes has a total area that is the same as the total area of the one or more first holes, and the first sub-box and the second sub-box each have a volume that is different from one another.