Composite Center Core for Reduction of Stray Magnetic Fields in Disk File Actuators
Original Publication Date: 1985-Oct-01
Included in the Prior Art Database: 2005-Feb-19
A composite center core for the reduction of stray magnetic fields in a disk file actuator solves previous design problems that led to high moving masses and a cantilevered structure with attendant resonance and stiffness concerns. Stray magnetic fields at a disk can erase data directly, be concentrated by the recording head to erase data indirectly, or cause errors through write asymmetry and peak shift. Fig. 1 shows the stator of a linear actuator with the armature removed. The armature is shown in Fig. 2. In the disk file actuator of Fig. 2, a stator 9 includes magnets 14, and a guide rod 10 comprising a center core composed of a nonmagnetic rod (such as stainless steel) 11 which is butt-soldered at 12 (or otherwise bonded) to a magnetically permeable rod (such as iron or cold-rolled steel) 13.