| 摘要 |
A brushless d.c. motor comprising a housing, an annular stator coil structure with the housing, a rotor concentric with the stator and comprising a body having an output shaft portion extending from one end thereof toward the forward end of the housing for connection to a mechanical load for driving the same and a permanent magnet arrangement on the periphery of the rotor body operatively associated with the stator coil structure, a first bearing near the forward end of the housing for rotatably supporting the shaft portion of the rotor and wherein there is provided a second bearing axially inwardly of the rear end of the rotor for rotatably supporting that end of the rotor and a circuit board located between the rear end of the rotor and the rear end of the housing. By virtue of the location of the second bearing a rigid and vibration free structure is provided for operation of the motor at high speed. By virtue of the location of the second bearing and the circuit board potting material can encapsulate the stator coil structure and circuit board thereby completely sealing all electrical sections of the motor so that they can withstand autoclave sterilization conditions. A fluid passage arrangement equalizes pressure applied to the first and second bearings so that they can withstand autoclave sterilization conditions.
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