Patent ID: 8256241

Claim:
An air conditioner comprising: a body panel that is provided in a ceiling of a room air-conditioned by the air conditioner and that has a blowoff port for air from the inside of an air conditioner body; a side wall installed in an upright position, along the outer periphery of the body panel; an air conditioner top plate provided so as to cover a surface of the side wall opposed to the body panel; a body suction port formed in the side wall of the air conditioner body; a heat exchanger provided in the vicinity of the body suction port, inside the side wall; a fan motor fixed to the air conditioner top plate; a centrifugal fan having a convex-shaped boss part fixed to a rotation shaft of the fan motor, the centrifugal fan sucking the air sucked via the body suction port and the heat exchanger as a result of the rotation of the rotation shaft, and blowing off the air to the room; and a airflow guide plate that isolates an air flow on the suction side of the centrifugal fan from an air flow on the blowoff side thereof, and that guides a blowoff flow of the centrifugal fan to the blowoff port of the body panel, wherein the centrifugal fan comprises: a main plate having a flat part provided on the outer peripheral side thereof, and the boss part provided at a central part thereof; a side plate having an airflow guide wall provided so as to surround the boss part with a predetermined distance therebetween; and a plurality of blades provided between the main plate and the side plate so as to be substantially orthogonal to a plane perpendicular to the rotation axis; and wherein, with the rotation of the plurality of blades, the centrifugal fan blows air from a suction port formed of a boss-side wall surface and a side plate end part opposite to the boss-side wall surface, toward a blowoff port formed of an outer peripheral side flat part of the main plate and an end part of the side plate opposite to the outer peripheral side flat part; wherein, when an edge part of the blade positioned on the down stream side of a blowing direction is taken as a blade rear edge part, the centrifugal fan has the following relationship: outer diameter of the side plate > outer diameter of the blade rear-edge part on side-plate side > diameter of the blade rear-edge part on main plate side ≧ outer diameter of the main plate; wherein the blade rear-edge part is positioned inside from a straight line connecting the connection point between the blade rear-edge part and the main plate, to the connection point between the blade rear-edge part and the side plate, as viewed from the rotation axis; and wherein the blade rear-edge part has a shape such that the distance from the rotational axis becomes larger from the main plate toward the side plate.