| 摘要 |
PROBLEM TO BE SOLVED: To make collapsible deformation occur adequately when an external force is applied thereto. SOLUTION: A supporting rib 40 projecting in a duct body 20 to support a second duct wall 24 from the inside is provided on a first duct wall 22. A slacking part 42 is formed at a boundary between the supporting rib 40 and the first duct wall 22. The slacking part 42 is formed in a projecting manner outward of the duct body 20 toward the supporting rib 40 from the first duct wall 22, and formed over approximately three quarters of a circumference along an outer circumferential part of the supporting rib 40. Thus, when an external force is applied to the first duct wall 22, the slacking part 42 is deformed in shape in an extending manner to permit the posture displacement of the supporting rib 40, and the duct body 20 is subjected to collapsible deformation. COPYRIGHT: (C)2008,JPO&INPIT
|
