| 摘要 |
PROBLEM TO BE SOLVED: To reduce noise while improving air blowing efficiency by high static pressure. SOLUTION: This blower is provided with a boss 1 and a blade 4. A curve formed by connecting a central point of respective circular arc lengths extending in the peripheral direction of overlapping respective concentric circles radially extending around an intersection between a plane and the rotational axis 30 with a projected blade 4, when vertically projecting the blade 4 on the plane vertical to the rotational axis 30, is defined as a central curve 6 in the peripheral direction. An angle formed of a straight line of connecting the intersection and a boss 1 side end point of the central curve 6 in the peripheral direction of the blade 4 and a straight line of connecting the intersection and an optional point of the central curve 6 in the peripheral direction, is set as an advance angleθwith the rotational direction of the blade 4 as positive. When a rate of change per unit length in the radial direction of this advance angleθis defined as the advance ratio, the blade 4 has a boss 1 side advance blade part having the advance ratio having a positive value in the radial direction and an outer peripheral side retreat blade part of the blade 4 having a negative value. The circular arc length of the blade 4 is long toward the outer peripheral side from the boss 1 side. COPYRIGHT: (C)2007,JPO&INPIT
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