Centrifugal fan and electronic device

Abstract

A centrifugal fan includes a fan rotating about a central axis; and a fan casing enclosing the fan and having an air intake port formed in an axial direction in which the central axis extends and an air exhaust port formed in an orthogonal direction orthogonal to the central axis, radiating fins being provided in the air exhaust port, a tongue portion close to the fan and an inner flow channel going around the fan from the tongue portion to the air exhaust port are formed in the fan casing, and the fan casing has a cover (metallic plate) forming at least one of a top face and a bottom face facing each other in the axial direction, and a protruding portion formed on the cover and projecting toward a blow-out side of the inner flow channel opposite the tongue portion.

1 . A centrifugal fan, comprising:
 a fan rotatable about a central axis; and   a fan casing enclosing the fan and having an air intake port in an axial direction in which the central axis extends and an air exhaust port in an orthogonal direction orthogonal to the central axis, and radiating fins in the air exhaust port,   wherein a tongue portion functionally adjacent to the fan, and an inner flow channel going around the fan from the tongue portion to the air exhaust port, are in the fan casing, and   the fan casing has:
 a metallic plate having at least one of a top face and a bottom face facing each other in the axial direction; and 
 a protruding portion on the metallic plate and projecting toward a blow-out side of the inner flow channel opposite the tongue portion. 
   
     
     
         2 . The centrifugal fan according to  claim 1 , wherein the metallic plate is a copper plate. 
     
     
         3 . The centrifugal fan according to  claim 1 , wherein the protruding portion is formed by recessing a part of the metallic plate. 
     
     
         4 . The centrifugal fan according to  claim 1 ,
 wherein the protruding portion has a triangular shape having a hypotenuse extending in a direction of crossing a main flow direction on the blow-out side of the inner flow channel when viewed from the axial direction.   
     
     
         5 . The centrifugal fan according to  claim 1 ,
 wherein a plurality of the protruding portions are spaced apart in the main flow direction on the blow-out side of the inner flow channel when viewed from the axial direction.   
     
     
         6 . The centrifugal fan according to  claim 1 ,
 wherein the protruding portion is on the air exhaust port side from the central axis in the main flow direction on the blow-out side of the inner flow channel when viewed from the axial direction.   
     
     
         7 . The centrifugal fan according to  claim 1 ,
 wherein the protruding portion is on one of the top face and the bottom face, and   a heat pipe connected to the radiating fins is on the other of the top face and the bottom face.   
     
     
         8 . An electronic device comprising:
 a centrifugal fan including:
 a fan rotatable about a central axis; and 
 a fan casing enclosing the fan and having an air intake port in an axial direction in which the central axis extends and an air exhaust port in an orthogonal direction orthogonal to the central axis, and radiating fins in the air exhaust port, 
 wherein a tongue portion functionally adjacent to the fan, and an inner flow channel going around the fan from the tongue portion to the air exhaust port, are in the fan casing, and 
 the fan casing has:
 a metallic plate having at least one of a top face and a bottom face facing each other in the axial direction; and 
 a protruding portion on the metallic plate and projecting toward a blow-out side of the inner flow channel opposite the tongue portion.