SCHRITTMOTOR MIT FEDERND GELAGERTEM ROTOR FUER DEN KOPFANTRIEB BEIM LESEN VON MAGNETISCHEN SCHEIBEN.

摘要

The disclosure relates to a technique for effectively floating the rotor (37) of a disc drive motor, thereby permitting small motions in the axial (non-critical) direction while maintaining significant stiffness of the radial (critical) direction. This is achieved by providing an electromagnetic actuator inluding a stepper motor having a housing, a stator located within the housing, and a rotor (37) positionable relative to the stator driving a motor shaft to wind and unwind a band (14) and thereby position the carriage. The drive shaft (12) passes through ball bearings (30) which support the shaft for rotation. The ball bearings themselves fit within an annular end bell portion (39) of the motor housing which defines a channel for the bearing. An injected elastomer (33) forms a tight-fitting ring between the bearings and the internal wall of the end bell (39), thereby radially supporting the outer race of the bearing. Preload springs (36) are then installed on both sides of the rotor between the internal end walls of the end bells and both outer races of the bearing. the installation of these springs effectively floats the rotor to allow some distortion of movement of the rotor in the axial direction, while minimizing or eliminating the radial deflection components.