A motor includes a shaft along a central axis, an inner ring fixed on an outer circumferential surface of the shaft, a tubular sleeve extending axially around the shaft, an outer ring fixed to an inner circumferential surface of the sleeve via an adhesive agent, a cap annularly expanding around the shaft and covering an axially upper side of the inner and outer rings, and a bearing portion including dynamic pressure grooves in at least one of an outer circumferential surface of the inner ring and the inner circumferential surface of the sleeve. In the bearing portion, a stationary portion and a rotating portion face each other across a gap where lubricating oil is present. At least one interface of the lubricating oil is in a radial gap between the inner and outer rings. The cap includes a recess recessed axially downward over an entire circumference. At least a portion of an outer circumferential surface of the recess portion is fixed by press-fitting to an inner circumferential surface of the sleeve.

A sintered metal bearing is formed of a porous body formed through sintering of a compact obtained through compression molding of raw-material power. The sintered metal bearing includes a dynamic pressure generating portion formed on an inner peripheral surface, the dynamic pressure generating portion including dynamic pressure generating groove array regions formed continuously to each other in an axial direction of the sintered metal bearing. The dynamic pressure generating groove array regions each include a plurality of dynamic pressure generating grooves arrayed so as to be inclined with respect to a circumferential direction of the sintered metal bearing. An axial dimension of the sintered metal bearing is set to 6 mm or less, and a density ratio of the sintered metal bearing is set to 80% or more and 95% or less.

A motor includes a shaft, a base portion, a stator, and a rotor. The shaft extends along a central axis extending in an axial direction. The base portion extends in a radial direction on one axial direction side of the shaft. The stator is located in another axial direction with respect to the base portion and surrounds the shaft. The rotor is rotatable around the central axis. The rotor includes a rotor tube portion, a magnet, and a rotor flange portion. The rotor tube portion surrounds the stator. The magnet is opposed to the stator in the radial direction. The rotor flange portion extends in a radially outer direction from one axial end portion of the rotor tube portion. The rotor tube portion includes a yoke tube portion and a hub tube portion. The yoke tube portion is located on a radially inside surface of the hub tube portion.

Provided is a base unit for use in a disk drive apparatus including a motor arranged to be capable of rotating about a central axis extending in a vertical direction. The base unit includes a base member arranged to extend radially to support the motor, and including a predetermined adhesion region and an outside region outside of the adhesion region; and a connector electrically connected to a wire arranged on the base member. The connector is adhered to the base member through an adhesive at the adhesion region of the base member. A wettability of the adhesive on the adhesion region is higher than a wettability of the adhesive on the outside region of the base member.

A rotating portion includes a hollow shaft extending along a central axis. The hollow shaft includes a through hole passing therethrough in an axial direction. The rotating portion includes an upper screw to close an upper opening that is an opening at an upper end portion of the through hole. The rotating portion includes a lower screw to close a lower opening that is an opening at a lower end portion of the through hole. The hollow shaft includes an upper groove portion into which the upper screw is screwed at the upper opening. The hollow shaft includes a lower groove portion into which the lower screw is screwed at the lower opening. A lubricating oil is in contact with the lower screw. The lower groove portion is shorter in axial length than the upper groove portion, and the lower screw is smaller in axial pitch than the upper screw.

A hollow shaft includes a hollow portion extending in an axial direction from an opening that is open at one end of the hollow shaft in the axial direction. The hollow shaft further includes a first communicating hole establishing radial communication between the hollow portion and an axial space between an upper lubricating oil and a lower lubricating oil. The hollow shaft further includes a second communicating hole establishing radial communication between the hollow portion and an unsealed space inside the motor. The unsealed space is connected to an external space outside the motor. The hollow shaft further includes a sealing member closing the opening. The hollow shaft has, in an inner peripheral surface facing the hollow portion, a recess recessed radially outward. A part of the sealing member is fitted into the recess.

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.

Provided is a base unit for use in a disk drive apparatus including a motor arranged to be capable of rotating about a central axis extending in a vertical direction. The base unit includes a base member arranged to extend radially to support the motor, and including a predetermined adhesion region and an outside region outside of the adhesion region; and a connector electrically connected to a wire arranged on the base member. The connector is adhered to the base member through an adhesive at the adhesion region of the base member. A wettability of the adhesive on the adhesion region is higher than a wettability of the adhesive on the outside region of the base member.

An oil-impregnated sintered bearing (8) includes a copper-iron-based sintered compact containing 40 mass % or more of copper, and has inner pores impregnated with an oil. The sintered compact has: a copper structure derived from copper powder (13) of partially diffusion-alloyed powder (11) in which copper powder (13) having a particle diameter of 20 m or less is diffused on and joined to a surface of iron powder (12) in advance; and a copper structure derived from elemental copper powder (14).

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.