Patent ID: 7791232
Filing Date: 2010-09-07
Classification: B24B,H02K,Y10T

Abstract:
1. A power tool, comprising: a housing having an electronically commutated motor disposed therein; the motor having a rotor and a stator, the rotor having permanent magnets, the stator having a lamination stack and windings wound therein; the rotor having a shaft, a sense magnet tray affixed to the shaft of the rotor in proximity to a sensor disposed in the housing, the sensor axially spaced from the sense magnet tray, a sense magnet affixed to the sense magnet tray, the sense magnet tray having a circumferential skirt that extends around an outer edge of the sense magnet, the skirt having a height at least equal to a height of the sense magnet; wherein a shortest uninsulated path between the sense magnet and a closest conductive part of the rotor is along a serpentine path that runs from the sense magnet, along an outer surface of the circumferential skirt and along a bottom of the sense magnet tray.