Centrifugal fan

Abstract

The application provides a centrifugal fan that can be easily positioned when it is installed in a device or apparatus, which can further improve positioning accuracy, and which can decrease noise, even if it is made thin. In the centrifugal fan in which an impeller is received inside a casing and air drawn in from a suction port formed on the casing by rotating the impeller is discharged from the casing to the outside of a blowing port, a circular protruded portion is formed on a peripheral edge of the suction port, and protrudes upwardly in a shaft direction from an upper surface of the casing.

1 . A centrifugal fan comprising:
 a casing formed by a lower casing and an upper casing having a suction port;   pillars interposed between the lower casing and the upper casing;   an impeller housed in the casing and having a circular shroud, a main plate,   and blades arranged between the circular shroud and the main plate; and a motor for rotating the impeller;   wherein a circular protruded portion for engaging with an object in which the centrifugal fan is installed is formed on a peripheral edge of the suction port, multiple concavities are formed on an upper surface of the upper casing and arranged outside the circular protruded portion,   wherein the circular protruded portion protrudes upwardly in a shaft direction from the upper surface of the upper casing, and   air sucked from the suction port by rotating the impeller is discharged from a blowing port formed between the upper casing and the lower casing.   
     
     
         2 . The centrifugal fan according to  claim 1 ,
 wherein the circular shroud has a circular protruded portion,   a circular groove is arranged on a lower surface of the circular protruded portion of the upper casing corresponding to the circular protruded portion of the circular shroud, and   a part of the circular protruded portion of the circular shroud is housed in the circular groove.   
     
     
         3 . The centrifugal fan according to  claim 2 ,
 wherein a labyrinth seal structure is formed between the circular groove and the circular protruded portion formed on the circular shroud.   
     
     
         4 . The centrifugal fan according to  claim 2 ,
 wherein radial ribs and circular ribs that connect the radial ribs are formed such that an individual concavity is formed in the radial ribs and the circular ribs.   
     
     
         5 . The centrifugal fan according to  claim 4 ,
 wherein the pillars are arranged outside of an outermost individual concavity.