A stator of a traditional electronically commutated motor usually comprises a pair of end caps located at opposite axial ends thereof and four bolts located outside of the stator and fixed to the end caps at four spaced locations thereof. A cooling fan is typically located inside the stator, within one of the end caps.
However, the bolts located outside of the stator occupy extra space, which is contrary to the trend of miniaturization. Furthermore, the size of the fan located inside the stator is limited by the size of the end caps, which limits the cooling capability of the fan.
USPTO Backgrounds
USPTO Backgrounds