Pivot bearing assembly providing damping for unit-to-unit consistency

• Main Authors: BUTLER; WALTER WAYNE, EDWARDS; JOHN ROBERT
• Format: Patent
• Language: English
• Published: 17.03.1998
• Edition: 6
• Subjects: BEARINGS; BLASTING; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; DYNAMO-ELECTRIC MACHINES; ELECTRICITY; ELEMENTS OR CRANKSHAFT MECHANISMS; ENGINEERING ELEMENTS AND UNITS; FLEXIBLE SHAFTS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; GENERATION; HEATING; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; LIGHTING; MECHANICAL ENGINEERING; PHYSICS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; SHAFTS; THERMAL INSULATION IN GENERAL; WEAPONS

A pivot bearing assembly for mounting to an enclosure of a head disk assembly to support a head stack assembly of a disk drive is disclosed. The pivot bearing assembly comprises a shaft for being affixed to the enclosure and defining a longitudinal axis, a first and second set of bearings, the second set of bearings longitudinally spaced from the first set of bearings, and each set of bearings surrounding a respective portion of the shaft. The pivot bearing assembly also comprises an inner sleeve member and an outer sleeve member, both sleeve members surrounding the shaft. A pair of channels is located between the outer and inner sleeve members. Alternatively, the pair of channels is located between the shaft and the sets of bearings. The channels contain a cured cast-in-place material, preferably, an ultra violet cured polyurethane compound having a hardness between approximately 24 Shore A to 79 Shore A. The material provides damping of any vibratory wave propagating between an outer surface of the outer sleeve member and the shaft. Furthermore, a portion of the cured cast-in-place material defines an exterior surface of the pivot bearing assembly.