1. Field of the Invention
The invention relates to a heat-dissipating device and a housing thereof, and in particular, the invention relates to an axial-flow fan and a housing thereof.
2. Description of the Related Art
In a normal electronic product such as a computer, electronic devices therein generate a lot of heat during operation. If the electronic devices are continuously operated at high temperature, they are easily damaged. Thus, to prevent damage, a heat-dissipating fan is normally disposed in the electronic product to dissipate heat therein to the surrounding.
The conventional heat-dissipating fan for the computer mainly includes a housing 11 and an impeller 12 with a plurality of blades. As shown in FIG. 1A and FIG. 1B, the housing 11 includes a plurality of stick-shaped ribs 13 to support a base thereof. When the fan operates, the air pressure, generated by an airflow passing through the blades, is changed from P0 at an inlet side A to P1 at an outlet side B. That is, the pressure difference is ΔP (P1−P0). When the pressure difference increases, air resistance also increases, diminishing heat-dissipation. After studying the relationship between the shape of the rib and the air pressure of the fan, the inventor has discovered that the ribs generate air resistance. Specifically, when the fan rotates, work is done on the air to generate the airflow. However, after flowing through the ribs, the airflow becomes turbulent and forms a vortex. Thus, the air pressure is reduced, and the heat-dissipation is also reduced.
Thus, it is important to reduce the air resistance generated by the ribs. Additionally, it is desirable to utilize the tangent velocity of the airflow so as to enhance the air pressure.