Patent ID: 8303274

Claim:
A miniature fan, comprising an electronically commutated drive motor ( 18 ) with an internal stator ( 68 ) equipped with a stator winding arrangement, and an external rotor ( 27 ) connected to a central shaft ( 62 ), on which external rotor is provided a permanent-magnet arrangement ( 66 ) that is in interaction with the internal stator ( 68 ), on which external rotor ( 27 ) is arranged a fan wheel ( 28 ) that is equipped with fan blades ( 26 ), further having a flange ( 40 ′) carrying a projection ( 82 ) for receiving a bearing tube ( 60 ) adapted for rotatably journaling said central shaft ( 62 ) of the external rotor ( 27 ), said bearing tube ( 60 ), in turn, supporting said internal stator ( 68 ), said internal stator ( 68 ) carrying, on its side facing the flange ( 40 ′), a first circuit board ( 86 ) bearing a Hall element ( 100 ) for control by said permanent-magnet arrangement ( 66 ) of the external rotor ( 27 ); a second circuit board ( 96 ) being provided, said flange ( 40 ′) defining a cavity ( 84 ) that serves to receive said first circuit board ( 86 ) equipped with electronic components, said cavity being provided in a boundary region between the flange ( 40 ′) and the electronically commutated drive motor ( 18 ), the second circuit board ( 96 ) carrying at least one galvanomagnetic sensor ( 100 ) which is configured to sense a magnetic field acting, from the permanent-magnet arrangement ( 66 ) of the external rotor ( 27 ), on an associated point on the stator ( 68 ), the axial extent of the fan blades ( 26 ) being dimensioned such that at least a portion of each fan blade extends from the fan wheel ( 28 ) to an outer region of the flange, in order to improve the volumetric air flow (V/t) and the differential air pressure (Δp) generated by the fan ( 20 ); the first circuit board ( 86 ) being electrically and mechanically connected to the second circuit board ( 96 ) via associated first connecting pins ( 104 , 106 ); the second circuit board ( 96 ) being electrically and mechanically connected to the internal stator ( 68 ) via associated second connecting pins ( 72 , 74 ), so that the bearing tube ( 60 ) and the circuit boards ( 89 , 96 ) can first be assembled together, before subsequent mounting into said fan ( 20 ) by inserting the bearing tube into said projection ( 82 ) of the flange ( 40 ′).