Impeller of centrifugal fan

Abstract

An impeller of a centrifugal fan having a casing and a multi-blade impeller rotatably supported by a blade holding base in the casing, wherein when the impeller is rotated air is sucked from an air suction port formed on one side wall of the casing, and a centrifugal force is applied on the air, so that air of high pressure is taken out through an outlet formed on a portion of an outer peripheral surface of the casing. An inner peripheral surface of the impeller is formed of a conical surface having a large diameter at the suction port and a small diameter at the blade holding base. The small diameter at the blade holding base is in the range of 70 to 90% of the large diameter at the suction port. The diameter of the inner peripheral surface of the impeller is reduced linearly from a portion at the suction side to a portion at the blade holding base side.

1 . A impeller of a centrifugal fan comprising: 
 a casing and    a multi-blade impeller rotatably supported by a blade holding base in said casing, wherein when said impeller is rotated air is sucked from an air suction port formed on one side wall of said casing, and a centrifugal force is applied on said air, so that air of high pressure is taken out through an outlet formed on a portion of an outer peripheral surface of said casing, wherein an inner peripheral surface of the impeller is formed of a conical surface having a relatively large diameter at the air suction port and a relatively small diameter at the blade holding base.    
   
   
       2 . The impeller of the centrifugal fan according to  claim 1 , wherein the small diameter at the blade holding base is in the range of 70 to 90% of the large diameter at the air suction port.  
   
   
       3 . The impeller of the centrifugal fan according to  claim 1 , wherein the diameter of the inner peripheral surface of the impeller is reduced linearly from a portion at the air suction port to a portion at the blade holding base.  
   
   
       4 . The impeller of the centrifugal fan according to  claim 2 , wherein the diameter of the inner peripheral surface of the impeller is reduced linearly from a portion at the air suction port to a portion at the blade holding base.  
   
   
       5 . The impeller of  claim 1 , wherein the diameter of the inner peripheral surface of the impeller is reduced continuously from a portion at the air suction port to a portion at the blade holding base.  
   
   
       6 . An impeller for a centrifugal fan comprising: 
 a casing having an air suction port formed on one side wall thereof and an outlet formed on a portion of an outer peripheral surface thereof; and    a multi-blade impeller; and    a blade holding base in said casing, wherein, 
 when said impeller is rotated air is sucked from the air suction port, and a centrifugal force is applied on the air, so that air of high pressure is taken out through the casing outlet, wherein  
 an inner peripheral surface of the impeller is formed of a conical surface having a relatively large diameter at the air suction port and a relatively small diameter at the blade holding base, and wherein  
 the small diameter at the blade holding base is in the range of 70 to 90% of the large diameter at the air suction port.  
   
   
   
       7 . The impeller according to  claim 6 , wherein the diameter of the inner peripheral surface of the impeller is reduced continuously from a portion at the air suction port to a portion at the blade holding base.  
   
   
       8 . The impeller according to  claim 7 , wherein the diameter of the inner peripheral surface of the impeller is reduced linearly from a portion at the air suction port to a portion at the blade holding base.