| 摘要 |
PROBLEM TO BE SOLVED: To facilitate manufacture, and silence noises by forming an impeller by crisscross arranging two main blades and two auxiliary blades having small areas, in a device wherein a fluid is moved in the axial direction by rotation of the impeller provided with blades around a boss fixed to a rotary shaft. SOLUTION: An impeller 1 is composed of a rotary shaft 2, a boss 3 fixed to the rotary shaft 2, main blades and auxiliary blades arranged around the boss 3. The main blades 4 and the auxiliary blades 5 are plate shaped blades attached to a circumference of the boss 3 in parallel with an axis, and two main blades 4 and two auxiliary blades are crisscross arranged. In each main blade 4, its width is wide, and its front side of a rotational direction is recessed and curved. Each auxiliary blade 5 is formed in an area smaller than that of the main blade 4, and is formed straightly so as to match with a radius line in order to improve separating at the time of mold. It is thus possible to facilitate manufacture of the impeller 1, and it is also possible to reduce costs.
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