Abstract: An apparatus and method for correcting static and dynamic imbalance with a single mass in a hard disk drive is disclosed. The method provides for determining a static imbalance of a hard disk assembly and for determining a dynamic imbalance of the hard disk assembly. A greater imbalance from the static imbalance and the dynamic imbalance is determined. A single mass is applied to the hard disk assembly to correct the greater imbalance.

Abstract: An improved disk drive system that employs a lubricant with improved charge control is provided. The disk drive system is comprised of a rotatably mounted magnetic disk. A rotor is coupled to the disk and rotatably retained by a stator. A bearing is formed that serves as an interface between the stator and the rotor. A motor coupled to the rotor rotates the magnetic disk via the rotor. Located in the bearing is a lubricant having a low relative electrical permittivity.

Abstract: A balancing mechanism for the spindle of a computer hard disk drive uses two, substantially flat wire clips at each end of the disk pack. The clips are designed so that one clip in each pair nests concentrically inside the other clip in the pair. Each clip is provided with a substantially identical imbalance in the installed position. If the imbalance vectors of each clip at one end of the disk pack are oriented 180 degrees apart, the resulting imbalance at that end of the pack is zero. Conversely, if the imbalance vectors are oriented at the same angle, the imbalance is maximized. Thus, the resolution of the imbalance provided by the clips is theoretically infinite between these limits, up to the precision of the clips. The orientation of the imbalance vector is controlled by the angle of the pair of clips relative to an index mark on the disk pack. The magnitude of the desired counterbalance is controlled by rotating the clips in each pair relative to each other.

Abstract: A hard disk drive spindle motor has a hub, a drive shaft, and a bearing therebetween. The spindle motor also has a ferrofluid seal to prevent any incidental oil emissions from the bearing from entering the drive. A ferrofluid cap is mounted on the axial end of the spindle motor for sealing the ferrofluid seal. The cap is a flat ring and has an elastomeric pad around its outer edge. The pad seats in a recess in the bore of the hub. The cap does not touch the shaft as it rotates with the hub about the shaft. Any excess ferrofluid from the ferrofluid seal is forced radially outward away from the shaft by centrifugal force. The cap contains the excess ferrofluid within the spindle motor and prevents it from entering other areas of the disk drive.

Abstract: A hard disk drive spindle motor has a hub, a drive shaft, and a bearing therebetween. The spindle motor also has a ferrofluid seal to prevent any incidental oil emissions from the bearing from entering the drive. A ferrofluid cap is mounted on the axial end of the spindle motor for sealing the ferrofluid seal. The cap is a flat ring and has an elastomeric pad around its outer edge. The pad seats in a recess in the bore of the hub. The cap does not touch the shaft as it rotates with the hub about the shaft. Any excess ferrofluid from the ferrofluid seal is forced radially outward away from the shaft by centrifugal force. The cap contains the excess ferrofluid within the spindle motor and prevents it from entering other areas of the disk drive.