A charging amount of lubricating oil (11) into an internal space of a housing (7) is adjusted so that, within a range of a use temperature, an oil level of the lubricating oil (11) is positioned on a lower side with respect to an upper end portion of a chamfered portion (8f) formed in an upper-end inner peripheral edge portion of a bearing member (8). The bearing member (8) integrally includes: a small-diameter cylindrical portion (81); and a large-diameter cylindrical portion (82). Under a state in which an upper end surface (8c) of the small-diameter cylindrical portion (81) is exposed to an atmosphere, the large-diameter cylindrical portion (82) is sandwiched from both sides in the axial direction with an annular member (9) and a bottom portion (7b) of the housing (7) so that the bearing member (8) is fixed along an inner periphery of the housing (7).

According to one embodiment, a disk device includes a first actuator assembly on a support shaft via a first bearing unit, and a second actuator assembly on the support shaft via a second bearing unit. The first bearing unit includes a first shaft on the support shaft, a first sleeve fixed to the first actuator block, and a bearing between the first shaft and the first sleeve. The second bearing unit includes a second shaft on the support shaft, separated from the first shaft, a second sleeve fixed to the second actuator block, and a bearing between the second shaft and the second sleeve. One axial end of the first shaft faces one axial end of the second shaft.

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).

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 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.

In a pair of sliding parts having sliding faces S that slide with respect to each other, at least one of the sliding faces S has a one-side peripheral edge (4a) and an other-side peripheral edge (4b) and includes: fluid introduction grooves (12) each of which has one end communicating with the other-side peripheral edge (4b), dynamic pressure generation grooves (11) each of which has one end communicating with the other-side peripheral edge (4b) and the other end being surrounded by a land portion, and a release groove (13) provided in the land portion, the release groove (13) communicating with the fluid introduction grooves (12). With the sliding parts, not only a liquid such as oil but also an oil mist serving as a mixture of oil and air can be sealed as a sealed fluid, and generation of oil mist itself can be reduced.

A technique for swinging swing arms stably by reducing vibrations of bearing units due to resonance in rolling bearings is provided. A pivot assembly bearing device 1 includes a shaft 10 extending in an axis Y1 direction, and an upper bearing unit 20 and a lower bearing unit 60 that are provided along the axis Y1 direction of the shaft 10. A natural frequency of the upper bearing unit 20 and a natural frequency of the lower bearing unit 60 in the axis Y1 direction of the shaft 10 differ from each other.

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 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 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.