| CPC F04D 29/441 (2013.01) [F04D 25/08 (2013.01); F04D 29/023 (2013.01); F04D 29/403 (2013.01); F04D 29/4226 (2013.01)] | 20 Claims |

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1. A fan structure comprising:
a fan impeller;
a motor having a rotation shaft connected to the fan impeller; and
a fan frame enclosing the motor and the fan impeller to form a flow passage, wherein the fan frame has a bottom wall and a side wall, the side wall includes a first relatively hard portion and a first relatively soft portion, wherein the first relatively hard portion has a hardness greater than that of the first relatively soft portion, and the first relatively soft portion serves as a part of a wall surface of the flow passage.
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