| 摘要 |
PURPOSE:To decrease the difference between the condensation and the rarefaction of a compressional wave, in discharge air flow from an impeller, so as to reduce the noise of a motor-driven blower, by shaping blades of an impeller, as their outer circumferential edges become sharp toward the outer circumference of the impeller. CONSTITUTION:An inlet port 9 is formed at the center of a casing 8, and a part of this casing 8 opposite to said inlet port 9, is attached to a motor frame 10. A centrifugal impeller 12 which has plural blades 11, is attached to a motor shaft 13 through a nut 14, a spacer 15 and a washer 16. Moreover, an air guide 19 which is formed as integrating diffusers 17 and return passages 18 connected to respective enlarged passages of the diffusers 17 in one body, is set under said impeller 12. In this case, the blades 11 are shaped as the outer circumferential edges of these blades 11 become sharp toward the outer circumference of the impeller 12, viewing from the point on a surface which is perpendicular to a rear face shroud 23. In this way, lag is generated in the time of departure of air flow from the blades 11, and thus, the noise level is lowered.
|
