Abstract: A disc drive includes a disc drive motor for rotating a magnetic storage disc. The disc drive includes a sealed disc drive chassis which provides a substantially contaminant-free cavity. A fixed member is coupled to the disc drive chassis and a rotor is rotatably about the fixed member for carrying a magnetic storage disc in the contaminant-free cavity. A bearing assembly between the rotor and fixed member allows rotation of the rotor relative to the fixed member. A gap defined between the rotor and the fixed member separates the bearing assembly from the contaminant-free environment and the magnetic storage disc. A barrier material in the gap has a characteristic which reduces contaminant flow thereby. The barrier material tends to prevent liquid and particulate contaminants from escaping from the drive motor and entering the sealed cavity.

Abstract: Starting of single phase permanent magnet direct current motors in the desired direction of rotation is accomplished by providing a look up table stored in memory giving the correct sign or polarity of current for the angular position of the permanent magnet rotor of the motor. This stored look up table is developed by initially injecting current pulses of opposite polarity at different angular positions of the rotor, determining the difference between the rise times, and mapping the sign and the magnitude of the differences versus angular position. Thereafter, to start the motor in the correct direction, it is only necessary to inject current pulses of opposite polarity to know the angular position of the rotor and the polarity of the current required to start the motor in the correct direction. After the motor has been started, it is commutated by blanking the drive current at the zero crossings of the back emf.

Abstract: A hydrodynamic bearing spindle motor for rotating at least one disc about a central axis in a data storage device comprises a base, a stationary member, a hub, and a stator. A hydrodynamic bearing interconnects the hub with the stationary member such that the hub is rotatable about the central axis. The stator is coaxial with the hub and has at least one stator winding that is distributed about its circumference. The distributed winding attenuates pure tone vibrations which become more noticeable with lower levels of background vibrations in hydrodynamic bearing spindle motors.

Abstract: An apparatus for rotatably journaling a rotor of a spindle motor about a shaft comprising a plurality of annular ring multi-pole magnets, each ring comprised of a plurality of axially aligned magnets whose polarity is alternated along the radius of the ring. The annular ring multi-pole magnets are disposed on both the rotor and stator of a spindle motor in opposition in attraction mode, or a complete offset repulsion mode with like poles facing one another with an full offset, thereby forming a radially stable magnetic bearing for maintaining rotor displacement about a shaft in conjunction with a conventional axial pivot.

Abstract: An "ironless" bearing spindle motor for rotating at least one disc about a central axis in a data storage device comprises a housing, a stationary member, a hub, and a stator. A rotor magnet is attached to the hub. A bearing interconnects the hub with the stationary member such that the hub and rotor magnet are rotatable about the central axis. The stator is coaxial with the hub and includes an ironless stator winding. The ironless stator winding minimizes low-harmonic acoustic vibration peaks in the spindle motor, resulting in a spindle motor having a very quiet operation.

Abstract: An apparatus for rotatably journaling a rotor of a spindle motor about a shaft comprising a plurality of annular ring multi-pole magnets, each ring comprised of a plurality of axially aligned magnets whose polarity is alternated along the radius of the ring. The annular ring multi-pole magnets are disposed on both the rotor and stator of a spindle motor in opposition in attraction mode, or a complete offset repulsion mode with like poles facing one another with an full offset, thereby forming a radially stable magnetic bearing for maintaining rotor displacement about a shaft in conjunction with a conventional axial pivot.

Abstract: A voice coil motor (VCM) for a small form factor hard disk drive having a contoured flux field in the air gap wherein adjoining regions of oppositely directed magnetic flux form a transition zone. In the preferred embodiment, the magnetic structure assembly is contoured or shaped. The magnetic structure assembly comprises pole pieces and magnets. The shaping may be of either of the pole pieces or of either of the magnets. The shaping may be along the top edge only, along the bottom edge only, or along both edges. Alternatively, the shaping may be accomplished in the transverse plane, that is by shaping the profile in thickness. The shaping can be done so that when the flux is falling in one gap it is rising in the other gap. In this manner, the sum of the flux in the two gaps remains the same.

Abstract: The present method and apparatus detects the rotor position of a brushless DC motor with an accuracy of .pi./m electrical radians (where m = the number of motor phases) within one electrical period, and provides enough information to enable starting the motor in the correct direction with certainty. After starting the motor in an open loop mode of one or two steps, a closed loop mode may be switched on, using a dynamic indirect position detection as is already well known in the technology. More specifically, the position at start is determined by the injection of short current pulses in different motor phases, each phase or pair of phases being energized first by a pulse of one polarity and of the opposite polarity. The sign of the time difference between the decay times of the induced voltages in the un-energized phase is detected.

Abstract: In a disc drive with an integrated casting comprising the housing for the stepper and spindle motors, the transducer is mounted on a normal bearing pivot assembly lightweight actuator arm and biasing strip spring. One end of the strip spring is mounted to a block and the effective force of the spring is aligned with the actuator arm running toward the stepper motor. The other, or head end of the actuator arm contains a gear sector having gear teeth on its face which mesh with a pinion on a motor shaft so rotation of the motor shaft across the face of the gear sector causes movement of the head mounting arm. The actuator arm is formed of a self-lubricating polymer or other lightweight self-lubricating material. This way, wear on the gear is reduced; and as the teeth are worn, the gear is still tightly biased against the pinion to maintain accurate movement of the actuator arm with rotation of the pinion.

Abstract: In summary, the stepper motor of this invention comprises a rotor anbd stator both mounted in a single housing (which may be a part of the base casting as described in the incorporated application) the bearings supporting the rotor for rotation within the housing both being located on the rotor shaft on the same side of the rotor adjacent one another, the opposite end of the single housing being covered with a sealed plastic cover. The bore of the lamination stack that forms the stator is piloted by machined surfaces into a high tolerance fit within the housing, and clamped in place with a simple wave washer/snap ring combination.