| 摘要 |
PROBLEM TO BE SOLVED: To reduce an air blowing noise by uniformizing the flow of air running toward a suction port of an air blowing casing by a guide part. SOLUTION: An air flow guide part 13d projecting to the rotary shaft 13c side is formed on an inside surface of a circumferential wall 13a of a rotary door 13. This air flow guide part 13d guides the flow of air running toward a suction port 21 after being introduced from an inside air introducing port 11 or an outside air introducing port so as to be uniformized, and is composed of plural projecting parts 13e and 13f formed in a waveform and a recess- projection shape on an inside surface of the circumferential wall 13a. When introducing air tries to flow along the inside surface of the circumferential wall 13a, the flow of introducing air can be forcedly deflected to the lateral side from the central side of an air fliter 30 and the suction port 21 by the air flow guide part 13d. As a result, air is distributed at almost uniform wind speed over the whole surface of the air filter 30, and the upstream side air flow of the air filter 30 is straightened, and since turbulence of the air flow is minimized, a noise by the turbulence of the air flow can be reduced.
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