Split ring mounting for disk drive spindle and actuator shafts

Abstract

In a magnetic disk drive, a stationary spindle shaft and a rotary actuator shaft are mounted to opposed walls of the drive housing in precise radial and axial alignment with one of the walls, despite relatively relaxed tolerances in the mounting components. At each shaft end, an axially directed fastener is surrounded by an alignment ring with two frusto-conical guide surfaces, one engaged with an enlarged head of the fastener and the other engaged with the associated shaft end. An axially inward tightening of the fastener brings the enlarged head and shaft end into engagement with their respective guide surfaces of the alignment ring. The fastener is tightened further to elastically elongate the fastener and create a tensile force which, through wedging action, urges the alignment ring radially outward into a firm frictional engagement with a rim of the selected wall, thus to radially align and integrally mount the shaft end with respect to the wall. One of the alignment rings for each shaft has an inclined radially outward edge which, in combination with a seal member that provides a reference surface, axially aligns the shaft relative to the selected wall. The opposite alignment ring has an axial radially outward wall, to accommodate a variance in the axial distance between the opposed housing walls.