| 摘要 |
PROBLEM TO BE SOLVED: To decrease abnormal noises a caused by a small opening angle of an air mix door. SOLUTION: A stepped portion 540, whose thickness changes in steps with decreased thickness of an air mix door 500 toward the tip, is provided at an end of the air mix door 500 opposite the center of an oscillation portion (shaft 530). Accordingly, even if a swirl is generated when the air passes through the tip 541 of the stepped portion 540, the generated swirl crashes into the next corner portion (step portion) so that the air flow passing the portion from air mix door 500 to the outer edge portion 222 of the opening is disturbed. Consequently, the abnormal noise caused by the generated swirl is controlled so as to decrease the abnormal noise caused by small opening angle of the air mix door 500.
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