| 摘要 |
PROBLEM TO BE SOLVED: To provide a low-noise electric blower whose air current sound and operation sound can be considerably reduced. SOLUTION: A soundproof case 14 covering a motor 4 and a fan case 12 and having an exhaust port 13 has an exhaust passage 16 for introducing an exhaust stream up to the exhaust port 13 in which sound absorbing materials 20a and 20b are arranged. Angles 17a and 17b are arranged in the exhaust passage 16. The sound absorbing material 20a is arranged with air layers 35a interposed between itself and an air current hitting surface 18a of the corner 17a. This improves damping effect of acoustic energy by reflection of sound at the corners 17a and 17b and the sound absorbing effect in the low-frequency range of the sound absorbing materials 20a and 20b in consequence of the air layers 35a. Not only the operation sound of the electric blower including high-frequency sound exhibiting a high level of sound pressure but also the air current sound in a low-frequency band which is generated on the current hitting surface can be considerably reduced. COPYRIGHT: (C)2009,JPO&INPIT
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