Patent ID: 9033680
Filing Date: 2015-05-19
Classification: F04D,H02K

Abstract:
1. An electric fan comprising: an electric motor including: a stator including stator magnetic poles; and a rotor including rotor magnetic poles and configured to rotate outside the stator, centering on the rotary shaft; an impeller disposed outside the rotor, the impeller including: an impeller body fixed to the rotor and including an opposed wall portion; and a plurality of blades fixed to the impeller body; one or more bearings for supporting the rotary shaft; and a casing including; a bearing holder by which the one or more bearings are held; and a base including an opposed wall portion opposed to the opposed wall portion of the impeller body in an axial direction of the rotary shaft and extending in a radial direction of the rotary shaft and combined with the impeller body to define a receiving space to receive the stator and the rotor, wherein a clearance is defined between the opposed wall portion of the base and the opposed wall portion of the impeller body to form a labyrinth structure for blocking entry of a liquid into the receiving space from radially outside of the rotary shaft; the opposed wall portion of the base and the opposed wall portion of the impeller body are shaped to form a volume expanding portion having a volume larger than other portions within the clearance; a first groove portion for expanding the clearance is formed in the opposed wall portion of the impeller body, the first groove portion extending in a direction apart from the base to define a part of the volume expanding portion; and a second groove portion for expanding the clearance is formed in the opposed wall portion of the base, the second groove portion extending in a direction apart from the impeller body to define a remaining part of the volume expanding portion;