Patent ID: 8727746

Claim:
A method of producing a mini-fan having a fan wheel equipped with fan blades ( 80 ), an electric drive motor ( 61 ) for driving said fan wheel, said drive motor ( 61 ) having an internal stator ( 90 ) and an external rotor ( 62 ), which rotor is formed with an annular supporting part ( 64 , 64 ′) made of plastic and connected to a shaft ( 60 ), said supporting part ( 64 , 64 ′) being implemented integrally with the fan blades ( 80 ) and having an axial projection ( 90 ′), and at least one annular permanent magnet ( 72 ; 72 ′) having hard ferromagnetic particles ( 74 ), said method comprising the steps of: forming, by two-component injection molding, first, said annular plastic supporting part ( 64 , 64 ′), connected to the shaft ( 60 ), and second, said annular rotor permanent magnet ( 72 ; 72 ′), of ferromagnetic particles ( 74 ) embedded in a plastic matrix material, along an inner surface ( 70 ) of said annular plastic supporting part ( 64 , 64 ′) so that at least a portion of a transition zone ( 76 ) between the supporting part ( 64 , 64 ′) and rotor permanent magnet ( 72 ; 72 ′) forms a mechanically engaging connection by contact melting together of a plastic portion of said annular supporting part and said plastic matrix material of said permanent magnet, the material forming the annular rotor permanent magnet ( 72 , 72 ′) being injected around said axial projection ( 90 ′); and assembling the thus-molded external rotor ( 62 ) onto said internal stator ( 90 ) to form the mini-fan.