Centrifugal fan

Abstract

The centrifugal fan includes an impeller for producing the flow of air by rotation, and a motor for rotating the impeller. The impeller includes a plurality of main blades and a plurality of auxiliary blades. In the centrifugal fan, the turbulent flow of air flowing near the outer surface of the cup part is suppressed and the noise of the centrifugal fan is reduced by connecting the auxiliary blades to the outer surface of the cup part. An opening passing through with respect to the center axis direction is formed between two adjacent auxiliary wings, and the opening end on the lower side of the opening is inclined towards a stator side, whereby some air that flowed to the outer surface efficiently flows into the cup part, thereby supplying air to the stator and suppressing temperature rise of the stator.

1 . A centrifugal fan comprising: 
 a cup part of substantially bottomed cylindrical shape with a cylindrical yoke portion having a predetermined center axis as center;    a field magnet fixed on an inner surface of the cup part;    an impeller, including a blade assembly connected to the cup part and arranged radially in an annular region on the outer side of the cup part, taking in air from the bottom side of the cup part and exhausting air in a direction away from the center axis when rotating with the cup part, the blade assembly including: 
 a plurality of main blades arranged along the periphery of the impeller; and  
 a plurality of auxiliary blades connected to the outer surface of the cup part and directly or indirectly connected with the plurality of main blades at an opening side of the cup part between the outer surface of the cup part and the plurality of main blades;  
   a housing including a side wall part for covering the periphery of the impeller, a base part for covering the opening side of the cup part, and a cover part formed with an air intake port facing the bottom of the cup part, a width of a flow path between the side wall part and the impeller gradually widening towards an air exhaust port;    a bearing mechanism for rotatably supporting the cup part with respect to the base part with the center axis as the center; and    a stator, fixed to the base part and having at least one part positioned in the cup part, for generating a torque having the center axis as the center between the field magnet.    
   
   
       2 . The centrifugal fan according to  claim 1 , wherein the width in the center axis direction of the impeller between the plurality of main blades and the plurality of auxiliary blades is less than or equal to ⅓ the length in the center axis direction of the plurality of main blades.  
   
   
       3 . The centrifugal fan according to  claim 1 , wherein the impeller includes a plurality of openings passing through with respect to the center axis direction between the plurality of auxiliary blades.  
   
   
       4 . The centrifugal fan according to  claim 3 , wherein edges on the base part side of the plurality of auxiliary blades are inclined towards the base part while extending from the opening of the cup part to the outer side; the opening ends on the base part side of the plurality of openings include the edges, and a region on the plurality of main blades side of the opening end is closer to the base part than a region on the center axis side.  
   
   
       5 . The centrifugal fan according to  claim 4 , wherein edges on the side away from the base part of the plurality of auxiliary blades are inclined towards the base part while extending to the outer side.  
   
   
       6 . The centrifugal fan according to  claim 1 , wherein the ends on the base part side of the plurality of main blades are coupled by an annular plate having the center axis as the center, and outermost regions of the plurality of auxiliary blades are connected to the regions on the inner side of the annular plate.  
   
   
       7 . The centrifugal fan according to  claim 1 , wherein each of the plurality of auxiliary blades is connected to one of the plurality of main blades.