Ball spindle for reduced friction rotary actuator in disk drive

A micro-Winchester disk drive including a base, a rotating storage disk mounted to the base, and a data transducer head incrementally rotationally positioned by a mass balanced rotary voice coil actuator mounted to the base and comprising:

• a support structure mounted to the base,
• a rotatable body having upper and lower bores generally coaxial to an axis of rotation of the rotatable body,
• an upper pivot bearing assembly defining an upper outer bearing race fixed to the support structure and including a plurality of equally dimensioned small bearing balls in the upper outer bearing race,
• a lower pivot bearing assembly defining a lower outer bearing race fixed to the support structure and including a plurality of equally dimensioned small bearing balls in the lower outer bearing race,
• an upper main ball bearing having a diameter greater than a diameter of the upper bore and in substantial alignment with the axis of rotation of the rotatable body and being positioned partially within the upper bore and in contact between the rotatable body and the plurality of small bearing balls of the upper pivot bearing assembly,
• a lower main bearing ball having a diameter greater than a diameter of the lower bore and in substantial alignment with the axis of rotation of the rotatable body and being positioned partially within the lower bore and in contact between the rotatable body and the plurality of small bearing balls of the lower pivot bearing assembly, and
• wherein the upper main bearing ball and the lower main bearing ball each have a diameter which is greater than a diameter of each of the equally dimensioned small bearing balls respectively of the upper pivot bearing assembly and the lower pivot bearing assembly and wherein the small bearing balls of each bearing assembly rotate around the main bearing ball in contact therewith.

A micro-Winchester disk drive including a base, a rotating storage disk mounted to the base, and a data transducer head incrementally rotationally positioned by a mass balanced rotary voice coil actuator mounted to the base and comprising:

• a rotatable body having an axis of rotation,
• a support structure mounted to the base for supporting said rotatable body, the support structure including an upper bore positioned above the rotatable body and a lower bore positioned below the rotatable body, the upper and lower bores being generally coaxial to the axis of rotation,
• an upper pivot bearing assembly defining an upper outer bearing race fixed to the rotatable body and including a plurality of equally dimensioned small bearing balls in the upper outer bearing race,
• a lower pivot bearing assembly defining a lower outer bearing race fixed to the rotatable body and including a plurality of equally dimensioned small bearing balls in the lower outer bearing race,
• an upper main ball bearing having a diameter greater than a diameter of the upper bore and in substantial alignment with the axis of rotation of the rotatable body and being positioned partially within the upper bore and in contact between the support structure and the plurality of small bearing balls of the upper pivot bearing assembly,
• a lower main bearing ball having a diameter greater than a diameter of the lower bore and in substantial alignment with the axis of rotation of the rotatable body and being positioned partially within the lower bore and in contact between the support structure and the plurality of small bearing balls of the lower pivot bearing assembly, and
• wherein the upper main bearing ball and the lower main bearing ball each have a diameter which is greater than a diameter of each of the equally dimensioned small bearing balls respectively of the upper pivot bearing assembly and the lower pivot bearing assembly and wherein the small bearing balls of each bearing assembly rotate around the main bearing ball in contact therewith.

A low stiction, shaftless actuator bearing for a rotary actuator assembly comprising:

• a rotatable actuator E-block body having an axis of rotation and having a head mounting arm with a long axis and having a transverse bore orthogonal to said long axis, said transverse bore having a bore diameter and having a central axis coincident with said axis of rotation and defining an upper and lower E-block bearing recess,
• an upper main bearing ball for engaging said upper E-block bearing recess, said upper main bearing ball having a diameter greater than said bore diameter,
• a lower main bearing ball for engaging said lower E-block bearing recess, said lower main bearing ball having a diameter greater than said bore diameter,
• an upper pivot bearing assembly having an upper ring of ball bearings, each ball bearing of said upper ring of ball bearings having a diameter less than the diameter of said upper main bearing ball, said upper ring of ball bearings configured in contact with a hemisphere of said upper main bearing ball opposite said upper E-block bearing recess, said upper ring of ball bearings lying in a plane orthogonal to said axis of rotation and having a center coincident with said axis of rotation, said upper pivot bearing assembly further including an upper bearing race for engaging said upper ring of ball bearings,
• a lower pivot bearing assembly having a lower ring of ball bearings, each ball bearing of said lower ring of ball bearings having a diameter less than the diameter of said lower main bearing ball, said lower ring of ball bearings configured in contact with a hemisphere of said lower main bearing ball opposite said lower E-block bearing recess, said lower ring of ball bearings lying in a plane orthogonal to said axis of rotation and having a center coincident with said axis of rotation, said lower pivot bearing assembly further including a lower bearing race for engaging said lower ring of ball bearings, and
• support means for supporting said upper pivot bearing assembly and said lower pivot bearing assembly adjacent said upper main bearing ball and said lower main bearing ball, respectively, said support means thereby rotatably supporting said E-block body for rotation about said axis of rotation.