"AC Axial Fan" bearing system generally recommend the best selection of ball bearings, because the fan heat fan bearing life often depends on its reliability characteristics of ball bearing system has been proven to have a high efficiency and low heat generation. Genus ball rolling friction, the rolling of a metallic bead, the contact surface is small, the friction coefficient is small; oil bearings and sliding friction, a large contact surface, after prolonged use, the oil will be volatilized, the bearing is easy to wear, friction coefficient, the larger the noise late , short life. Good "AC Axial Fan" in addition to ventilation volume, high pressure outside, reliability is very important, bearing in the form of fan used in this very important quality. Oil-bearing fan uses copper-based sinter powder made by using oil-lubricating bearings need to reduce the number of sliding friction, lubricant made from lithium grease Stuttgart oil blend. With the long run, oil "AC Axial Fan" within the bearing will evaporate and dry, the friction coefficient increases, the fan operates affected may appear different sound, speed not even turn phenomenon.