| 摘要 |
PROBLEM TO BE SOLVED: To provide an air passage opening/closing device capable of sufficiently reducing abnormal sound. SOLUTION: This device is constituted by arranging a projection part 34e for forming a wall surface inclined to a main flow direction of an air flow flowing in a gap of a seal seat part of a face opening part and a face door 34 in a truncated chevron shape. The air flow therefore can be more surely stirred as compared with an invention provided with a projection part (rib) constituting a wall surface parallel to the main flow direction of the air flow. As a result, since a vortex to be a cause of abnormal sound can be effectively sheared or extinguished, stable generation of the vortex to be the cause of abnormal sound by a prescribed period can be suppressed and abnormal sound can be surely reduced. COPYRIGHT: (C)2005,JPO&NCIPI
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