| 摘要 |
PROBLEM TO BE SOLVED: To reduce turbulence noise by suppressing exfoliation of air flow from tip part wall surfaces in suction opening sides of a first and a second blade part 62, 63. SOLUTION: A plurality of first and second blade parts 62, 63 provided on an outer circumference part in a radial direction of an impeller 7 with a fixed interval in a circumference direction are inclined toward a rotation direction (direction indicated by an arrow) of the impeller 7 to form forward blades with keeping number of the first and the second blade parts same. Forward angleϕof the first and the second blade parts 62, 63 is set to 20°to form forward blades. Consequently, flow in angles of air and angles of the first and the second blade parts 62, 63 can be made roughly same, exfoliation of air flow from the tip part wall surface in the suction port side of the first and the second blade parts 62, 63 can be eliminated. Consequently, since generation of turbulence due to exfoliation from the tip part wall surface in the suction port side of the first and the second blade parts 62, 63 can be suppressed, turbulence noise can be reduced. COPYRIGHT: (C)2007,JPO&INPIT
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