Centrifugal fan design to decrease noise and slim down the fan

A centrifugal fan comprising:

• a rotor that has a rotor yoke;
• an impeller that has a blade and is coupled to the outer periphery of the rotor yoke;
• a motor that rotates the rotor;
• and
• a casing that has a suction opening and a discharge opening, and houses the rotor, the impeller, and the motor,
• the impeller rotating together with the rotor discharging air sucked in through the suction opening to the outside of the casing through the discharge opening, wherein
• the rotor yoke has a top plate portion, a cylindrical body portion, and a conical portion connecting the top plate portion and the body portion,
• an inner periphery part of the blade on the rotor yoke side is formed so as to tilt along the conical portion on an outer peripheral surface of the rotor yoke,
• an inner periphery part of a surface of the blade extends to the inner periphery side, in such a manner as to overlap with the conical portion in an axial direction of the motor, and
• a certain clearance is formed between the inner periphery part of the blade and the conical portion of the rotor yoke.