Patent ID: 7492070

Claim:
A cooling fan comprising: a casing having a surrounding wall that defines front and rear openings for passage of fluid flow therethrough and that has an inner wall surface which defines an accommodating space; a circuit board disposed in said accommodating space and including a substrate and a control circuit, said substrate having a center portion that has a peripheral edge, and a plurality of spaced apart connecting beams that extend from said peripheral edge of said center portion and that are connected directly and securely to said inner wall surface of said surrounding wall, said control circuit being disposed on said center portion of said substrate; a hollow shaft secured directly to and protruding transversely from said circuit board into said accommodating space, and defining a rotation axis; a stator mounted securely on said center portion of said substrate of said circuit board, surrounding said hollow shaft, and coupled to said control circuit; a fan blade unit disposed in said accommodating space and including an annular hub journalled rotatably to said hollow shaft, surrounding said stator, and having an inner wall; and a rotor mounted on said inner wall of said hub and surrounding and coupled magnetically to said stator so as to rotate together with said fan blade unit about said rotation axis when said stator is actuated.