| 摘要 |
PROBLEM TO BE SOLVED: To provide an air duct structure for effectively reducing noise generated in an air duct. SOLUTION: A tail pipe 19 is connected to an exhaust port 18a of a muffler 18. This tail pipe 19 is formed by arranging a speed increase air duct 22a having the cross-sectional area smaller than a main air duct 21 in the main air duct 21 for flowing an exhaust wind exhausted from the muffler 18. A pipe diameter of this speed increase air duct 22a is formed so as to become smaller than a pipe diameter of the main air duct 21, to increase a flow speed of an exhaust flow in this speed increase air duct 22a. A sound absorbing material 23 is arranged in this speed increase air duct 22a. This sound absorbing material 23 is formed by fitting a super heat resistant sound absorbing material such as glass wool in a midway part of the speed increase air duct 22a, to effectively reduce the noise by exhaust vibration of a high frequency area. COPYRIGHT: (C)2008,JPO&INPIT
|
