Patent ID: 8007239
Filing Date: 2011-08-30
Classification: F04D

Abstract:
1. A cooling fan comprising: an impeller having a plurality of blades; and a housing having a base, a sidewall extending from a periphery of the base with an air outlet defined therein, and a cap covering the sidewall; a chamber formed between the cap, the base and the sidewall, the impeller being rotatably received in the chamber and configured for generating an airflow; and an air channel formed between tip portions of the blades and an inner face of the sidewall, the air outlet having a near section and a far section, the airflow first reaching the near section and then the far section; wherein the base of the housing has a protrusion extending into the air outlet, the protrusion is disposed at the near section of the air outlet and configured for guiding the airflow flowing towards the far section from the near section of the air outlet, and a maximum height of the protrusion occupies substantially a half of a height of the sidewall of the housing.