Patent ID: 6572346
Filing Date: 2003-06-03
Classification: F04D

Abstract:
A cooling fan comprising:a housing (10), the housing (10) having a bottom plate (11) and a flange (12) with an opening formed at the center of the bottom plate (11); a stator (20) received in the housing (10) and securely mounted on the flange (12), the stator (20) having a sleeve (21) inserted in the opening of the flange (12), a coil (22) provided outside the sleeve (21), an upper pole sheet (22) and a lower pole sheet (24) provided outside the sleeve (21) and at a top and a bottom of the coil (22) respectively and coaxial with the coil (22), a circuit board (25) provided outside the sleeve (21) and beneath the lower pole sheet (24), and an oil-retaining bearing (28) inserted in the sleeve (21); a rotator (40) received in the housing (10), the rotator (40) having a cap (41) covering the stator (20), a ring-like permanent magnet (43) secured on an inner wall of the cap (41), a bushing (42) provided between the cap (41) and the permanent magnet (43), a spindle (44) formed at the center of the cap (41) and inserted through the oil-retaining bearing (27) and secured by a collar (28); and a dustproof disk provided outside the sleeve (21) and between the circuit board (25) and the lower pole sheet (24) and received in the cap (41) of the rotator (40), whereby, a gap between the circuit board (25) and the cap (41) is sealed by the dustproof disk such that dust will not enter into the inside of the rotator (40).