Abstract: The present invention discloses a disk drive motor comprising a rotor having an annular space formed therein coaxially with the axis of rotation, and balancing member accommodated in the annular space and capable of changing its mass distribution circumferentially along the circle of the annular space. In case of any imbalanced rotation occurring during the rotation, the balancing member temporarily gather to a portion of the annular space where the mass imbalance is taking place. However, when the motor speed exceeds the value at which resonance takes place due to coincidence between the frequency of the vibration of the balancing member and the natural frequency of the motor, the balancing members move to a position symmetrical with the point of mass imbalance to eliminate the mass imbalance, thereby suppressing the run-out.

Abstract: The present invention discloses a disk drive motor comprising a rotor having an annular space formed therein coaxially with the axis of rotation, and balancing member accommodated in the annular space and capable of changing its mass distribution circumferentially along the circle of the annular space. In case of any imbalanced rotation occurring during the rotation, the balancing member temporarily gather to a portion of the annular space where the mass imbalance is taking place. However, when the motor speed exceeds the value at which resonance takes place due to coincidence between the frequency of the vibration of the balancing member and the natural frequency of the motor, the balancing members move to a position symmetrical with the point of mass imbalance to eliminate the mass imbalance, thereby suppressing the run-out.

Abstract: A spindle motor comprises a stationary shaft, a rotor hub rotatably mounted by ball bearings to the stationary shaft, and annular sealing members disposed between the outer surface of the stationary shaft and the inner side of the rotor hub axially outwardly of the ball bearings. The sealing member is directly fitted onto the outer race of the corresponding ball bearing. The outer race of each ball bearing is high precision finished so that the sealing member is definitely coaxial with the stationary shaft regardless of the finishing accuracy on the inner side of the rotor hub. Accordingly, the radial distance between the inner side of the sealing member and the outer surface of the stationary shaft can be minimized with high precision offering an excellent labyrinth effect.

Abstract: A brushless motor comprising a stator core having a plurality of tooth portions disposed peripherally at intervals, coils wound in a required manner on a plurality of tooth portions, an annular rotor magnet disposed in opposition to the stator core and having N poles and S poles alternately disposed, and a position detecting sensor for detecting the rotating angular position of the rotor magnet. The stator core is formed by laminating an anisotropic steel sheet in which the easily magnetizable axis of the crystal is in a specific direction.

Abstract: A spindle motor comprises a stationary shaft, a rotor hub rotatably mounted by ball bearings to the stationary shaft, and annular sealing members disposed between the outer surface of the stationary shaft and the inner side of the rotor hub axially outwardly of the ball bearings. The sealing member is directly fitted onto the outer race of the corresponding ball bearing. The outer race of each ball bearing is high precision finished so that the sealing member is definitely coaxial with the stationary shaft regardless of the finishing accuracy on the inner side of the rotor hub. Accordingly, the radial distance between the inner side of the sealing member and the outer surface of the stationary shaft can be minimized with high precision offering an excellent labyrinth effect.

Abstract: A disk drive apparatus in which a hard disk is fitted on a disk-fitting outer peripheral portion of a rotor hub. A gap is defined on the outer periphery of the rotor hub such that the axial height of the gap decreases radially inward. An elastic ring member, which is appropriately tensed in the circumferential direction, fits in the gap so as to exert a contracting force which serves to clamp the hard disk between itself and a disk supporting surface. The hard disk can be securely and easily fixed to the rotor hub with uniform application of the clamping pressure over the entire circumference, even when the axial height of the whole disk drive apparatus is reduced.

Abstract: A spindle motor comprises a stationary member, a hub for rotation relative to the stationary member, bearings provided between the stationary member and the hub, and a labyrinth seal provided outside one of the bearings. In particular, the labyrinth seal includes a plurality of labyrinth units. Each labyrinth unit is consisted mainly of a first member mounted to the stationary member and a second member mounted to the hub.

Abstract: A spindle motor having a housing, a hub member rotatable relative to the housing, a bearing disposed between the housing and the hub member, a rotor magnet mounted on the hub member, and a stator disposed in a facing relationship with the rotor magnet. The hub member includes a supporting wall portion, which cooperates with the stator to constitute an air seal structure. A magnetic fluid seal is provided at a position outward of the bearing, and includes a conductive plate for grounding static electricity. The bearing is comprised of a radial ball bearing, which includes certain improvement.

Abstract: Disclosed is a spindle motor comprising: a housing, a hub member which is rotatable with respect to the housing and to which a recording member is attached, and a bearing arranged between the housing and the hub member and having an outer member which is rotatably attached thereto through the intermediation of a plurality of spherical members, the hub member being fixed to the above-mentioned outer member by press fitting or shrinkage fitting, and the inner periphery of the hub member being equipped with an annular recess in correspondence with a ball lodging grooved formed on the outer member.