Abstract: An improved disk stack assembly for a hard disk drive (HDD) includes a generally cylindrical hub with flange having a downward sloping conical flange surface. The conical flange surface is defined between a radially inner circular ridge and a radially outer circular edge. The bottom disk in the stack is in contact with the flange inner circular ridge. The disk stack assembly also includes a disk clamp with a contact surface having a contact rim that is in contact with either the radially inner portion of the top disk in the stack or a spacer ring. The clamp contact rim is located at approximately the same radial distance from the hub's central cylindrical axis as the flange circular ridge so that the clamping force is applied to the disks close to the area where the disk stack is supported on the conical flange surface.

Abstract: An improved disk stack assembly for a hard disk drive (HDD) includes a generally cylindrical hub with flange having a downward sloping conical flange surface. The conical flange surface is defined between a radially inner circular ridge and a radially outer circular edge. The bottom disk in the stack is in contact with the flange inner circular ridge. The disk stack assembly also includes a disk clamp with a contact surface having a contact rim that is in contact with either the radially inner portion of the top disk in the stack or a spacer ring. The clamp contact rim is located at approximately the same radial distance from the hub's central cylindrical axis as the flange circular ridge so that the clamping force is applied to the disks close to the area where the disk stack is supported on the conical flange surface.

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 apparatus and method for correcting single plane and coupled plane imbalance with a single mass in a hard disk drive. The method provides for measuring a single-plane imbalance of a hard disk assembly and for measuring a coupled-plane imbalance of the hard disk assembly. A greater imbalance from the single-plane imbalance and the coupled-plane imbalance is determined. A single mass is applied to the hard disk assembly to correct the greater imbalance.

Abstract: A disk clamp for securing data storage disks to the hub of a spindle motor in a hard disk drive has a circumferential rib protruding from a lower surface of the disk clamp. A complementary recess is formed in the hub of the spindle motor for closely receiving the rib on the disk clamp. The inner diameter of the rib and the outer diameter of the recess are closely toleranced to provide a very precise centering feature for mounting and aligning the disk clamp with respect to the hub and spindle motor. This design reduces the complexity of the tooling and fixtures required to complete the assembly and the overall part cost is reduced.

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.