Image Number 10 for United States Patent #5917258.
A high speed electric motor for automotive applications that is designed to effectively minimize vibration of its component parts and thus suppress noise generated during its operation. The motor incorporates acoustic engineering principles including surface vibration control, acoustic radiation efficiency, active intensity field control and noise control using acoustic materials to reduce overall vibration of the motor components and the motor noise sensed by the passenger of the vehicle. In one aspect, a bearing assembly for an electric motor is disclosed. The electric motor is of the type including a housing defining an internal chamber, an armature disposed within the internal chamber and having a rotatable shaft, and magnet means for inducing rotational movement of the armature shaft. The bearing assembly includes a bearing member for supporting the armature shaft for rotational movement and a bearing housing defining an internal bore that accommodates at least a portion of the bearing member. The bearing housing may comprise a vibration energy absorbing material, and is dimensioned such that an inner wall portion of the bearing housing defining the internal bore is in contacting engagement with an outer surface of the bearing member to facilitate absorption of vibration energy from the bearing member.