公开(公告)号：US3803430A

公开(公告)日：1974-04-09

申请号：US30488572

申请日：1972-11-08

申请人： MOTOROLA INC

发明人： COSTA H ,  FOSTER V ,  THORNTON C

IPC分类号： H02K33/18 ,  G04C3/16 ,  H02K21/14 ,  H02K37/00 ,  H02K37/14 ,  H02K21/12

CPC分类号： H02K21/14 ,  G04C3/16

摘要： A miniature electric motor is disclosed wherein a synthetic bobbin or frame has a rotor inside of a central cylindrical cavity, the rotor being supported in bearings which include large diameter flanges bonded to the bobbin. The windings are disposed around the bearing flanges and in grooves whose bottom surfaces are tangential to the cylindrical cavity. The windings thus assist in holding the bearing flanges to the bobbin and form part of the motor framework. The angular bottom surfaces effects increase in the number of turns in the windings and effects an increase in the rotor diameter and thus in the motor torque. A slightly elliptical ring yoke of high permeability and low remanence surrounds and is bonded to the bobbin, the minor axis of the ellipse being at a slight angle to the normal of axis of the field created by the windings to create poles for stopping the rotor at a predetermined position. The major axis of the ellipse is only slightly larger than the minor axis to keep the starting torque requirements low, thereby preventing increase in power consumption.