According to one embodiment, a disk device includes a disk-shaped recording medium, a base accommodating the recording medium, the base including a bottom wall, a sidewall on a peripheral portion of the bottom wall, and a rib on a part of an upper surface of the sidewall, a first cover on a part of the upper surface of the sidewall, and a second cover on a first surface of the rib and above the first cover. The rib includes a first region with a first width, a second region with a second width less than the first width, and the first surface with a fixed width around an entire circumference of the rib. The first region and the second region are located corresponding to a side portion of the recording medium.

A shaft member for a fluid bearing device includes, on an outer peripheral surface thereof, two bearing surfaces (31 and 32) separated from each other in an axial direction, and a middle relief portion (33) formed between the bearing surfaces (31 and 32) and having a diameter smaller than a diameter of the bearing surfaces. The middle relief portion (33) includes a cylindrical surface portion (331) having a ground surface, and stepped portions (332) arranged on both axial sides of the cylindrical surface portion and having a diameter difference from the cylindrical surface portion.

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 spindle motor according to one aspect of the present disclosure includes a shaft member, a baseplate having a through hole in which the shaft member is inserted and fixed, and a rotor member disposed on one side in an axial direction of the baseplate and rotatably supported through the shaft member. In a peripheral groove formed in an inner peripheral surface of the through hole, a gap between the shaft member and the baseplate is sealed by adhesive on the one side in the axial direction and the other side in the axial direction opposite to the one side, so that a confined volume of air is formed.

A fluid dynamic bearing device includes a shaft disposed along a center axis, a sleeve cylindrically extending around the shaft, a thruster that closes a lower end of the sleeve, dynamic pressure grooves in the shaft or the sleeve, and a lubricating oil present therebetween. The shaft includes a shaft main body and a shaft flange extending radially outward from a lower end of the shaft main body. An inner peripheral surface of the sleeve includes a first inner peripheral surface that faces an outer peripheral surface of the shaft main body in the radial direction and a second inner peripheral surface that faces an outer peripheral surface of the shaft flange in the radial direction. The sleeve includes a sleeve inner lower surface and a circulation hole.

A slider may include a first side-edge surface, a second side-edge surface, and an air-bearing surface (ABS) comprising: a first side cavity adjacent to the first side-edge surface, and a first island side blocker situated at a mouth of the first side cavity, wherein: a first outer surface of the first island side blocker forms a portion of the first side-edge surface, a second outer surface of the first island side blocker is recessed from the first side-edge surface, a first side opening is situated on a leading side of the first island side blocker, and a second side opening is situated on a trailing side of the first island side blocker.

Provided are at least two bearings; an outer shaft having a tubular shape and supporting the bearings at an outer circumferential surface; and an inner shaft housed in the outer shaft with one end extending out from one opening part of the outer shaft. The inner shaft includes a male thread part at least at a portion extending out from the outer shaft.

A pivot assembly bearing device includes a shaft having an outer peripheral surface and a rolling bearing fixed to the shaft. An annular sealing surface axially overlapping with at least a part of an end surface of the rolling bearing is provided on an axially outer side of the rolling bearing. An oil-repellent film is annularly formed on at least one of the sealing surface and a part of the outer peripheral surface of the shaft located axially outward from the rolling bearing.

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 bearing device includes an annular hub cap facing an inner ring. An inner annular surface of the hub cap abuts a part of one end surface of the inner ring which extends from an inner peripheral edge to an intermediate position located on the way from the inner peripheral edge to an outer peripheral edge. An annular adhesive retaining portion is formed between the area extending from the intermediate position to the outer peripheral edge of one end surface and at least an inclined annular surface of the hub cap.