| 摘要 |
PROBLEM TO BE SOLVED: To inhibit the reduction of the quantity of air blow and the increase of the specific sound level while inhibiting the upsizing of a scroll, and to reduce the NZ sound and low frequency noise. SOLUTION: The dimension NG1 on the intake 76 side in the dimension W from the outer edge of a fan 71 to the inner wall of a scroll side board 74a is made smaller than the dimension NG2 on the opposite side from the intake 76 only in a prescribed rangeΘfrom a nose part 74c toward the end of winding in a scroll casing 74, and a wall part 74d near a nose part 71c on the intake 76 side is made to project from a wall part 74c near the nose part 71c on the opposite side from the intake 76 toward the end of winding. Therefore, the reduction of the quantity of air blow and the increase of the specific sound level is inhibited, while the upsizing of the scroll casing 74 is inhibited, and in addition, the NZ sound and low frequency noise is also reduced.
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