There are a lot of products need to use small, thin axial flow type cooling fans, such as 7, 2006250, 7300, 7400 within 10 mm thickness of these tiny ultra-thin cooling fans, in 3007 a cooling fan for columns, often heard a noise problem, the customer said as the growth of the time with the amount of noise problem more and more, what's the solution? Best the most effective way is to change the better bearing, at present most of the manufacturers of 3007 fan fan is made of oil type copper bearing, the roughness of bearing started under the action of lubricating oil, good voice, in the long run, oil decreases, and the noise came out, if with double ball bearings, improve good voice, is so thin, and only can do such a small ball in addition, in view of the 3007 type oil cooling fan noise problem, chi made the following several aspects to improve, first, the independent drive designed model 3007 bearing, fully cooperate with the mould size of bearing, such precision is better than male die to general a lot of fan bearing a lot. Second, open mould core shaft,. Third, do a smaller blades balance coefficient, make the balance better, more balanced cooling fan operation. Fourth, the use of hydraulic structure, make the lubricating oil less volatile, the performance of the extended mute. From the above three aspects, which can effectively extend mute effect of the cooling fan to more than one year, but the cost will be higher than ordinary about 0. 8 yuan, to mute the customer can consider this mould.