1. Field of the Invention
The present invention relates to a cooling fan, and more particularly to a cooling fan with a self-lubricating bushing which can lengthen the bushing's useful life.
2. Description of Related Art
A cooling fan is commonly used to remove heat from an area. It is generally used for devices which will generate a lot of heat during operation, such as a computer, VHS, or duplicator.
A conventional cooling fan is partly shown in FIG. 7. The fan is constructed to have a rotor, a stator, a circuit board and a housing. The rotor has a spindle (80) with a groove (81) near the head of the spindle (80). A bushing (90) is mounted in a sleeve formed in the housing. The spindle (80) is inserted into the bushing (90), and the head extends out from the lower end of the bushing (90). A retaining ring (82) is attached into the groove (81) to fix the spindle (80) to the bushing (90). A lubricant seal (91) is disposed on the upper end of the bushing (90).
During operation, friction in the spindle (80) and the bushing (90) generates a lot of heat, so the lubricant in the bushing (90) will gradually be exuded from the seal (91) to lubricate the spindle (80) and the bushing (90).
However, after extended operation, the lubricant seal (91) loses its effectiveness due to consumption or drying of the lubricant. When this happens, the bushing or the spindle will be destroyed, and the fan will fail.
A cooling fan with a self-lubricating bushing in accordance with the present invention tends to mitigate and/or obviate the aforementioned problem.