Patent ID: 11009032

Abstract:
A centrifugal fan includes a motor, an impeller, a circuit board, and a casing. The motor has a stator and a rotatable rotor. The impeller is fixed to and rotates with the rotor. The casing has a lower casing recessed downward and provided with a board housing portion accommodating the circuit board. The impeller includes a boss portion, blade portions, an upper shroud, and a lower shroud. The blade portions are disposed at intervals in the circumferential direction on an outer peripheral surface of the boss portion and extend radially outside. The upper shroud is connected to at least a portion of each of the blade portions on the upper side. The lower shroud is connected to at least a portion of the blade portion on the lower side. At least a portion of the lower end surface of the blade portion faces the upper surface of the circuit board.