Air intake duct

Abstract

There is provided an air intake duct capable of fully achieving intake-air noise attenuation effect. The air intake duct has a duct wall section formed of resin in form of tube and configured to introduce external air into an internal combustion engine or alternate power supply system. The duct wall section is provided with a silencing member formed of a lamination of a surface layer formed of a non-woven fabric to which thermosetting resin is impregnated and a ventilation adjusting layer formed of an extendable paper material having a surface in which a plurality of concave and convex portions are formed, and the silencing member includes at least one pair of the surface layers on front and back surfaces of at least one pair of the ventilation adjusting layers, and an intermediate layer is formed between the paired ventilation adjusting layers, the intermediate layer being formed of a same material as that of the surface layer.

1 . An air intake duct having a duct wall section formed of resin in form of tube and configured to introduce external air into an internal combustion engine or alternate power supply system, wherein
 the duct wall section is provided with a silencing member formed of a lamination of a surface layer formed of a non-woven fabric to which thermosetting resin is impregnated and a ventilation adjusting layer formed of an extendable paper material having a surface in which a plurality of concave and convex portions are formed, and   the silencing member comprises at least one pair of the surface layers on front and back surfaces of at least one pair of the ventilation adjusting layers, and an intermediate layer is formed between the paired ventilation adjusting layers, the intermediate layer being formed of a same material as that of the surface layer.   
     
     
         2 . The air intake duct according to  claim 1 , wherein the intermediate layer is bonded to the ventilation adjusting layers by means of bonding agent. 
     
     
         3 . The air intake duct according to  claim 1 , wherein the silencing member has a thickness of 1.0 to 3.0 mm. 
     
     
         4 . The air intake duct according to  claim 1 , wherein the silencing member has ventilation resistance of 1.0 to 4.0 kPa·s/m. 
     
     
         5 . The air intake duct according to  claim 1 , wherein the silencing member is located so as to close the hole portion formed to the duct wall section. 
     
     
         6 . The air intake duct according to  claim 1 , wherein the silencing member is formed by means of insert-molding to the duct wall section.