| 摘要 |
PROBLEM TO BE SOLVED: To realize a high efficiency and a low noise of an axial flow fan by inhibiting a turbulent flow of an air at the time of a suction. SOLUTION: Coaxial taper surfaces 22, 23 to a rotation center of a fan 1 are formed on a casing 12 surrounding a rotary vane 3 and an inclined portion 3A is formed on the rotary vane 3 along the taper surface 22 of a suction side. Thereby, an air flow at the time of a suction is made smooth to inhibit a turbulent flow. A large wind quantity and a large static pressure can be generated and a noise is also reduced by projecting a tip end of the rotary vane 3 from an upper surface of a boss portion 2 and enhancing a suction efficiency.
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