Axial-flow heat-dissipation fan

Abstract

An axial-flow heat-dissipation fan including a frame and a blade wheel is provided. The frame has an inlet, an outlet, and an inner wall connected between the inlet and the outlet. The inner wall surrounding the blade wheel has at least one rough region. The blade wheel is rotatably disposed in the frame and located between the inlet and the outlet, and an air flows into the frame via the inlet and flows out of the frame via the outlet by rotation of the blade wheel. A gap exists between a blade end of the blade wheel and the inner wall. A laminar flow is generated at the gap when the blade wheel is rotating and the blade end passes through the rough region so as to prevent a backflow generated at the gap, wherein a flowing direction of the backflow is opposite to a flowing direction of the air flow.

Dependencies are inferred from the claim text.