| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a duct 2 which is compact and excellent in silencing characteristics. <P>SOLUTION: The duct 2 consists of a body 4 and an outer layer 6. The outer layer 6 is laid on the outer peripheral surface of the body 4. The body 4 is tubular. The body 4 consists of an inner layer 8 and a foam layer 10. The foam layer 10 is laid on the outer peripheral surface of the inner layer 8. The inner layer 8 consists of a first ventilation layer 12 and a reinforcing body 14. The outer layer 6 consists of a second ventilation layer 16 and a non-ventilation layer 18. The first ventilation layer 12 and the second ventilation layer 16 are made of a nonwoven fabric. The foam layer 10 contains interconnected cells. The non-ventilation layer 18 is made of a resin film. The resin film is wound spirally. The width W1 of the resin film is smaller than a spiral pitch P. The side edge 30 of the resin film is separated from the adjacent side edge 30 thereof. By this separation, grooves 32 are formed on the surface of the duct 2. In each of the grooves 32, the second ventilation layer 16 is exposed. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
