Mini-fan

Abstract

A mini-fan has a fan wheel ( 64 ) equipped with fan blades ( 80 ), and an electrical drive motor ( 61 ) for driving that fan wheel. The drive motor ( 61 ) has a permanent-magnet external rotor ( 62 ) and an internal stator ( 90 ), which latter is implemented as a claw pole stator having pole pieces ( 88, 110 ) whose claw poles ( 84, 86 ) engage into one another. Arranged between the pole pieces is a coil former ( 57 ) that comprises a central portion ( 54 ) to which are joined two side parts ( 50, 56 ), located opposite one another, one of which is implemented as a carrier for electrical elements ( 96, 98 ) of the motor ( 61 ).

1 . A mini-fan having 
 a housing defining an air inlet opening ( 14 ):    a fan wheel ( 64 ) equipped with fan blades ( 80 ) for pulling air in through said air inlet opening ( 14 );    an electrical drive motor ( 61 ) for driving that fan wheel, said drive motor ( 61 ) including    a permanent-magnet external rotor ( 62 );    an internal stator ( 90 ), having sheet-metal pole pieces ( 88 ,  110 ) formed with claw poles which interdigit with each other, and    a coil former ( 57 ) located between said pole pieces ( 88 ,  100 ) and having a central portion ( 54 ) connecting two mutually opposed side pieces ( 50 ,  56 ), wherein at least one of said side pieces ( 50 ) serves as a carrier for electrical components ( 96 ,  98 ) of said drive motor ( 61 ).    
   
   
       2 . The mini-fan according to  claim 1 , wherein 
 the carrier ( 50 ) is formed with orifices ( 122 ,  124 ) for insertion of the claw poles of the pole piece ( 110 ) adjacent to it.    
   
   
       3 . The mini-fan according to  claim 2 , wherein 
 at least the pole piece ( 110 ) adjacent to the carrier ( 50 ) is equipped, at least locally, with a plastic part ( 114 ,  116 ) that is fixedly bound to the carrier ( 50 ).    
   
   
       4 . The mini-fan according to  claim 3 , 
 wherein the plastic part ( 114 ,  116 ) extends into a region between two adjacent claw poles ( 84 ,  86 ).    
   
   
       5 . The mini-fan according to  claim 3 , wherein 
 the plastic part ( 114 ,  116 ) is equipped, on its side adjacent to the carrier ( 50 ), with a projection ( 120 ), which projection is welded to the carrier ( 50 ).    
   
   
       6 . The mini-fan according to  claim 3 , wherein 
 the plastic part ( 114 ,  116 ) extends at least partially over at least one of said claw poles ( 84 ,  86 ).    
   
   
       7 . The mini-fan according to  claim 6 , 
 wherein a claw pole ( 84 ,  86 ) is equipped with recesses ( 126 ) into which plastic of the plastic part ( 114 ,  116 ) engages.    
   
   
       8 . The mini-fan according to  claim 1 , further comprising 
 a tube ( 52 ) made of soft ferromagnetic material, arranged inside the coil former ( 57 ).    
   
   
       9 . The mini-fan according to  claim 8 , 
 wherein the tube ( 52 ) of ferromagnetic material functions as a magnetic return path for the pole piece ( 88 ,  110 ).    
   
   
       10 . The mini-fan according to  claim 8 , 
 wherein the tube ( 52 ) is equipped, near the carrier, with at least one recess that extends over a portion of the tube periphery and through which plastic of the coil former ( 57 ) extends into the interior of the tube ( 52 ).    
   
   
       11 . The mini-fan according to  claim 10 , 
 wherein the plastic that extends into the interior of the tube ( 52 ) is configured to serve as part of an axial bearing for journaling the permanent-magnet external rotor ( 62 ).    
   
   
       12 . The mini-fan according to  claim 1 , wherein said fan housing ( 12 ) defines a generally circular air inlet opening ( 14 ) and 
 a sealing ring ( 24 ) of elastomeric material is provided adjacent a rim of said air inlet opening ( 14 ).    
   
   
       13 . The mini-fan according to  claim 12 , 
 wherein the sealing ring ( 24 ) is arranged on a circuit board ( 22 ) that is provided adjacent the air inlet opening ( 14 ).    
   
   
       14 . The mini-fan according to  claim 13 , further comprising 
 a temperature sensor ( 28 ), arranged on the circuit board ( 22 ).    
   
   
       15 . The mini-fan according to  claim 14 , 
 wherein the circuit board ( 22 ) comprises a strut ( 26 ) that extends into an airflow path defined by said air inlet opening ( 14 ) and serves as a carrier for the temperature sensor ( 28 ).    
   
   
       16 . The mini-fan according to  claim 1 , 
 wherein a temperature sensor ( 28 ) is provided; and conductors ( 140 ,  142 ) leading to the temperature sensor ( 28 ) are applied onto housing portion ( 144 ) of said fan using a hot-stamping method.    
   
   
       17 . The mini-fan according to  claim 1 , 
 wherein the fan blades ( 80 ) extend substantially parallel to the rotation axis ( 82 ) of the mini-fan.    
   
   
       18 . The mini-fan according to  claim 1 , 
 wherein said housing ( 20 ;  220 ) has at least one lateral air outlet opening ( 16 ).    
   
   
       19 . The mini-fan according to  claim 1 , 
 further comprising    mounting feet ( 53 ;  36 ′,  38 ′) that also serve, at least in part, for electrical connection of the fan.    
   
   
       20 . The mini-fan according to  claim 1 , wherein 
 a two-phase stator winding ( 58 ) that is wound in bifilar fashion is provided on the coil former ( 57 ).    
   
   
       21 . The mini-fan according to  claim 1 , wherein 
 a housing part ( 212 ), in which at least one permanent magnet ( 226 ,  228 ) is mounted by plastic injection molding, is provided adjacent the rotor ( 62 ).    
   
   
       22 . The mini-fan according to  claim 21 , 
 wherein the at least one permanent magnet is implemented as a plastic-matrix flexible magnet ( 226 ,  228 ).