| 摘要 |
For many applications, it is desirable to use fans which weigh less than 30 grams and are driven by electric motors not more than a few centimeters in size. Mass-producing products this small, which nevertheless must be extremely reliable, poses unique manufacturing challenges, which are best overcome by an improved structure which is susceptible to automation. Preferably, the fan motor is electronically commutated and has an internal stator (50) and an external rotor (22) supported on a central rotor shaft (34). The shaft is journaled within a bearing tube (70) supporting first and second rotor bearings (72, 76). By injection-molding the bearing tube (70) with first and second axial extensions (90′, 90″), the extensions can hold the bearings in place and insure uniform manufacturing quality and a desirably long service life. One of the extensions can also be shaped to abut against a circuit board (46) which supports components which control commutation.
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