Cross-flow fan, molding die, and fluid feeder
A cross-flow fan includes a plurality of fan blades circumferentially spaced from each other. The fan blade has an inner edge portion on the radially inner side, and an outer edge portion on the radially outer side. A blade surface extends between the inner edge portion and the outer edge portion. The blade surface includes a pressure surface on the rotation direction side of the fan and a suction surface on the opposite side. In cross-section orthogonal to the rotation axis of the fan, the fan blade has a concave portions formed at the pressure surface and the suction surface. A plurality of concave portions are formed at pressure surface. Side fan provides excellent blowing capacity. Also disclosed are a molding die for use in production of the cross-flow fan, and a fluid feeder provided with the cross-flow fan.
1. A cross-flow fan comprising a plurality of vane portions provided to be circumferentially spaced apart from each other, each having an inner edge portion arranged on a radially inner side to/from which air flows in/out and an outer edge portion arranged on a radially outer side to/from which air flows in/out, wherein
said vane portion has a blade surface extending between said inner edge portion and said outer edge portion and including a pressure surface arranged on a rotation direction side of the cross-flow fan and a suction surface arranged on a back side of said pressure surface,
said vane portion has such a blade cross-sectional shape that a concave portion is formed at said pressure surface and said suction surface when said vane portion is cut along a plane orthogonal to a rotation axis of the cross-flow fan,
a plurality of said concave portions are formed at at least one of said pressure surface and said suction surface, and
the number of said concave portions formed at said pressure surface is greater than the number of said concave portions formed at said suction surface.
2. The cross-flow fan according to claim 1 , wherein
said vane portion has a flection portion formed by flexing a center line of said blade cross-sectional shape extending between said inner edge portion and said outer edge portion, at a plurality of points, and
said concave portion is formed by said flection portion.
3. The cross-flow fan according to claim 2 , wherein said flection portion is flexed such that a depth of said concave portion is larger than a thickness of said vane portion at at least one point.
4. The cross-flow fan according to claim 1 , wherein said concave portion is formed in the proximity of said inner edge portion and said outer edge portion.
5. The cross-flow fan according to claim 1 , wherein said concave portion is formed at a blade central portion between said inner edge portion and said outer edge portion.
6. The cross-flow fan according to claim 1 , wherein said concave portion is formed at said pressure surface and said suction surface to repeatedly appear in a direction in which said inner edge portion is connected with said outer edge portion.
7. The cross-flow fan according to claim 1 , wherein said concave portion formed at said pressure surface forms a convex portion at said suction surface, and said concave portion formed at said suction surface forms a convex portion at said pressure surface.
8. The cross-flow fan according to claim 1 , wherein
in said blade cross-sectional shape, said concave portion is formed between convex portions appearing at said blade surface, and
said concave portion and said convex portions are formed to be alternately aligned in a direction in which said inner edge portion is connected with said outer edge portion.
9. The cross-flow fan according to claim 1 , wherein said vane portion has said blade cross-sectional shape having a generally constant thickness between said inner edge portion and said outer edge portion.
10. The cross-flow fan according to claim 1 , wherein said blade cross-sectional shape is approximately W-shaped.
11. The cross-flow fan according to claim 1 , wherein the cross-flow fan is made of resin.
12. A fluid feeder comprising a blower configured to include the cross-flow fan of claim 1 and a driving motor coupled to said cross-flow fan to rotate a plurality of said vane portions.