In certain embodiments, a motor includes a shaft positioned adjacent a sleeve for relative rotation. The sleeve includes a first radial recirculation channel. The shaft and sleeve form first and second gaps. The first gap is configured to form a pump seal, is positioned above the first radial recirculation channel, and has a width measured between the shaft and sleeve. The second gap is configured to form a journal bearing, is positioned below the first radial recirculation channel, and has a width measured between the shaft and sleeve. The width of the first gap is greater than the width of the second gap.

A fluid bearing apparatus includes a stationary member and a rotating member. A bearing surface of the stationary member and a bearing surface of the rotating member are arranged opposite to each other with a minute gap therebetween. The minute gap has a fluid arranged therein. At least one of the bearing surfaces includes a first dynamic pressure groove array. The first dynamic pressure groove array includes a plurality of first dynamic pressure grooves arranged unevenly at irregular intervals in a circumferential direction.

A fluid bearing apparatus according to a preferred embodiment of the present invention includes a shaft arranged to extend along a central axis extending in a vertical direction; a rotating portion arranged opposite to an outer circumferential surface of the shaft, and arranged to be capable of rotating about the central axis with respect to the shaft; a lubricating oil arranged in a gap between the rotating portion and each of upper and lower outer circumferential surfaces of the shaft; a first groove defined in at least one of a middle outer circumferential surface of the shaft and a portion of an inner circumferential surface of the rotating portion, the portion being opposite to the middle outer circumferential surface, the first groove being arranged to extend along a circumferential direction; a plurality of second grooves each of which is defined in an upper surface of the rotating portion; and a plurality of communicating holes each of which is defined in the rotating portion, and is in communication with the first groove and a corresponding one of the second grooves.

A stationary portion includes a stator unit including coils in an annular shape with a central axis as a center; a base portion below the stator unit; and a housing defining an interior space in which a rotating portion, a bearing portion, and the stator unit are accommodated. The base portion includes a through hole extending through the base portion in an axial direction to join an outside of the housing and the interior space to each other; a sheet covering an upper opening of the through hole to close the through hole; a filler covering a lower opening of the through hole; and a vent passage defined in at least one of the base portion and the sheet to join the through hole and the interior space to each other.

In a spindle motor, a cup portion of a base member includes a cylindrical portion coaxial or substantially coaxial with a central axis extending in a vertical direction and a bottom plate portion defined integrally with the cylindrical portion, and located to close a lower portion of the cylindrical portion. The bearing mechanism is inside of the cup portion and an outer circumferential surface of the bearing mechanism and an inner circumferential surface of the cylindrical portion include a first adhesive layer located therebetween. The base member includes a communicating hole that passes through the bottom plate portion in an axial direction. The communicating hole includes a second adhesive layer located therein.

A base portion of a motor includes an inner bottom plate portion, a recessed portion and groove portions recessed upward from a lower surface of the inner bottom plate portion, and at least one through hole passing through the inner bottom plate portion in an axial direction. The groove portions extend from the recessed portion toward land portions of a circuit board on a lower surface of the base portion. Conducting wires are drawn out from coils above the base portion to a draw-out surface through the at least one through hole, and are passed through communicating openings and the groove portions to be soldered to the land portions. Each of the at least one through hole is covered with the sealant. Drawing the conducting wires out of the recessed portion through the groove portions prevents the sealant in the recessed portion from overflowing toward the land portions.

A spindle motor includes a stationary portion, a rotating portion arranged to rotate about a central axis extending in a vertical direction, and a bearing portion arranged to support the rotating portion such that the rotating portion is rotatable with respect to the stationary portion. The stationary portion includes a stator unit including a plurality of coils arranged in an annular shape with the central axis as a center; a base portion arranged below the stator unit; and a housing arranged to define an interior space in which the rotating portion, the bearing portion, and the stator unit are accommodated. The base portion includes a through hole arranged to pass through the base portion in an axial direction to join an outside of the housing and the interior space to each other; a sheet arranged to cover an upper opening of the through hole to close the through hole; a filler arranged to cover a lower opening of the through hole; and a vent passage defined in at least one of the base portion and the sheet to join the through hole and the interior space to each other. Thus, the filler can be easily put into the through hole.

A fluid dynamic bearing apparatus includes a stationary body, a rotating body, and a lubricating oil arranged therebetween. One of the stationary and rotating bodies includes a shaft. Another one of the stationary and rotating bodies includes a sleeve. The sleeve includes a communicating hole arranged to pass therethrough in an axial direction or obliquely with respect to the axial direction. A groove array is defined in the stationary body or the rotating body to cause the lubricating oil to flow into the communicating hole. An opening area of an inlet of the communicating hole may be arranged to be greater than a cross-sectional area of a tubular portion of the communicating hole to make it easier for the lubricating oil to flow into the communicating hole. Further, the shape of the inlet may be modified to make a loss coefficient at the inlet lower than a loss coefficient at an outlet. This contributes to preventing a leakage of the lubricating oil.

A spindle motor according to an embodiment includes a base plate, a rotor magnet fixed to a rotor assembly positioned at one surface side of the base plate and a magnetic attraction plate fixed at the one surface side of the base plate so as to face the rotor magnet. An opposite area of the base plate facing the magnetic attraction plate includes a coated area covered by an epoxy electric discharge coating film, and the magnetic attraction plate is fixed to the opposite area via at least one of an epoxy adhesive and an acrylic adhesive.

In a spindle motor, a cup portion of a base member includes a cylindrical portion coaxial or substantially coaxial with a central axis extending in a vertical direction and a bottom plate portion defined integrally with the cylindrical portion, and located to close a lower portion of the cylindrical portion. The bearing mechanism is inside of the cup portion and an outer circumferential surface of the bearing mechanism and an inner circumferential surface of the cylindrical portion include a first adhesive layer located therebetween. The base member includes a communicating hole that passes through the bottom plate portion in an axial direction. The communicating hole includes a second adhesive layer located therein.