| 摘要 |
PROBLEM TO BE SOLVED: To provide a fan rotated at uniform rotating speed to improve fan operating region characteristics and to increase a heat dissipating efficiency with a fan section with superposed fan blades, or a fan section wherein a mounting angleθ1 of blade roots of a plurality of fan blades is 53°or less and the blade edges 46°or less, or a fan section wherein the blade root density of a plurality of fan blades is 1.5 or more, and the blade edge density is 1 or more. SOLUTION: This fan improved in operation region characteristics comprises at least the fan section and a drive unit. The drive unit allows the fan section to maintain constant rotating speed, and the fan section comprises at least a hub and the plurality of fan blades radially extended outward along the periphery of the hub. In the plurality of fan blades, the front fan blade is superposed on the following fan blade, or the mounting angle of the blade root is 53°or less and the blade edge is 46°or less, or blade root density is 1.5 or more and blade edge density is 1 or more. The fan section is rotated at constant speed to improve the heat dissipating characteristics of the fan. COPYRIGHT: (C)2006,JPO&NCIPI
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