Sound insulation component for a rigid structural member of an automobile

Abstract

A sound-insulation component for a rigid structural member, of the type including a mass-spring system ( 12 ) includes at least one layer of a heavy mass ( 16 ) and one layer defining a spring ( 14 ), and a sound absorption system ( 18 ) with two layers having different air-flow resistances. The structural member is a metal sheet, the mass-spring system ( 12 ) is provided on one side of the rigid structural member ( 10 ), and the sound absorption system ( 18 ) is provided on the other side of the rigid structural member ( 10 ). The first layer ( 22 ) among the two layers of the sound absorption system ( 18 ) consists of a non-woven fabric having an adjustable air-flow resistance. Application in the sound insulation of automobiles.

1 . Sound-proofing component for a rigid structural member, of the type comprising a mass/spring system ( 12 ) which comprises at least one layer ( 16 ) of heavy mass and a layer ( 14 ) which forms a spring, and a system ( 18 ) for acoustic absorption having two layers which have differing levels of resistance to air passage, characterised in that the structural member ( 10 ) is a metal sheet, the mass/spring system ( 12 ) is arranged at one side of the rigid structural member ( 10 ), the acoustic absorption system ( 18 ) is arranged at the other side of the rigid structural member ( 10 ), and the opposing surfaces of the structural member which are covered by the mass/spring system ( 12 ) on the one hand and the acoustic absorption system ( 18 ) on the other hand are opposite each other and of the same size. 
   
   
       2 . Sound-proofing component according to  claim 1 , characterised in that a first ( 22 ) of the two layers of the acoustic absorption system ( 18 ) has an adjustable level of resistance to air passage. 
   
   
       3 . Sound-proofing component according to  claim 2 , characterised in that the first ( 22 ) of the two layers of the acoustic absorption system ( 18 ) is formed by a non-woven material. 
   
   
       4 . Sound-proofing component according to  claim 3 , characterised in that the non-woven material is based on an unsaturated polyester combined with cellulose or “Nylon”. 
   
   
       5 . Sound-proofing component according to  claim 1 , characterised in that the second ( 20 ) of the two layers of the acoustic absorption system ( 18 ) is porous and flexible. 
   
   
       6 . Sound-proofing component according to  claim 5 , characterised in that the second ( 20 ) of the two layers of the acoustic absorption system ( 18 ) is formed by a material selected from a felt and a foam. 
   
   
       7 . Sound-proofing component according to  claim 1 , characterised in that the acoustic absorption system ( 18 ) comprises a layer of foam which has a high level of complexity. 
   
   
       8 . Sound-proofing component according to  claim 1 , characterised in that the mass/spring system ( 12 ) comprises a layer which forms a spring ( 14 ) and which is adjacent to the rigid structural member ( 10 ). 
   
   
       9 . Sound-proofing component according to  claim 1 , characterised in that it further comprises, at the side of the spring/mass system ( 12 ) opposite the rigid structural member ( 10 ), a sound-proofing complex ( 18 ′) which is selected from a complex which has two layers ( 20 ′,  22 ′) which have differing levels of resistance to air passage, and a complex formed by a layer ( 18 ″) of foam which has a high level of complexity. 
   
   
       10 . Sound-proofing component according to  claim 1 , characterised in that the rigid structural element ( 10 ) is a metal sheet which separates the passenger compartment of a vehicle from a space selected from an engine compartment, a wheel housing and an exhaust device. 
   
   
       11 . Sound-proofing component according to  claim 2 , characterised in that the second ( 20 ) of the two layers of the acoustic absorption system ( 18 ) is porous and flexible. 
   
   
       12 . Sound-proofing component according to  claim 2 , characterised in that the acoustic absorption system ( 18 ) comprises a layer of foam which has a high level of complexity. 
   
   
       13 . Sound-proofing component according to  claim 2 , characterised in that the mass/spring system ( 12 ) comprises a layer which forms a spring ( 14 ) and which is adjacent to the rigid structural member ( 10 ). 
   
   
       14 . Sound-proofing component according to  claim 2 , characterised in that it further comprises, at the side of the spring/mass system ( 12 ) opposite the rigid structural member ( 10 ), a sound-proofing complex ( 18 ′) which is selected from a complex which has two layers ( 20 ′,  22 ′) which have differing levels of resistance to air passage, and a complex formed by a layer ( 18 ″) of foam which has a high level of complexity. 
   
   
       15 . Sound-proofing component according to  claim 2 , characterised in that the rigid structural element ( 10 ) is a metal sheet which separates the passenger compartment of a vehicle from a space selected from an engine compartment, a wheel housing and an exhaust device. 
   
   
       16 . Sound-proofing component according to  claim 3 , characterised in that the second ( 20 ) of the two layers of the acoustic absorption system ( 18 ) is porous and flexible. 
   
   
       17 . Sound-proofing component according to  claim 3 , characterised in that the acoustic absorption system ( 18 ) comprises a layer of foam which has a high level of complexity. 
   
   
       18 . Sound-proofing component according to  claim 3 , characterised in that the mass/spring system ( 12 ) comprises a layer which forms a spring ( 14 ) and which is adjacent to the rigid structural member ( 10 ). 
   
   
       19 . Sound-proofing component according to  claim 3 , characterised in that it further comprises, at the side of the spring/mass system ( 12 ) opposite the rigid structural member ( 10 ), a sound-proofing complex ( 18 ′) which is selected from a complex which has two layers ( 20 ′,  22 ′) which have differing levels of resistance to air passage, and a complex formed by a layer ( 18 ″) of foam which has a high level of complexity. 
   
   
       20 . Sound-proofing component according to  claim 3 , characterised in that the rigid structural element ( 10 ) is a metal sheet which separates the passenger compartment of a vehicle from a space selected from an engine compartment, a wheel housing and an exhaust device.