McCormick, Paulding & Huber
Motor
 A spindle motor includes a housing, a shaft member fixed in the housing, a rotor rotatably supported on the shaft member, a rotor magnet mounted on the rotor, and a stator placed facing with the rotor magnet. The housing and the shaft member are made of materials different in hardness and a sleeve having substantially the same level of hardness as the shaft member is placed between the housing and the shaft member. A bushing is provided between bearing members and the rotor which is rotatably supported by the bearing members. The bushing and a yoke which is mounted on the rotor are secured together in the axial middle part of the bushing. In addition, through holes which enable communications between the interior and exterior area of the motor are provided in the bushing. 
Nippon Densen Corporation
G G H H F H
G11B G11B H02K H02K F16J H02K
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Hiroyuki Kiyoharu Yoichi Takashi
Yonei Noguchi Mori Yokoyama