A bearing structure includes a rotating shaft, a thrust collar, and a first thrust bearing. The rotating shaft has a central axis. The thrust collar is mounted on the rotating shaft. The first thrust bearing includes a first dynamic pressure generating mechanism. The first dynamic pressure generating mechanism faces the thrust collar. The relation Rt>Rf1 is satisfied, where Rt represents a length from the central axis to the outer circumferential edge of the thrust collar, and Rf1 represents a length from the central axis to the outer circumferential edge of the first dynamic pressure generating mechanism.

A ball bearing includes an inner ring, an outer ring, a plurality of balls rollably provided between the inner ring and the outer ring, and a cage configured to hold the plurality of balls at equal intervals in a circumferential direction. The cage includes a plurality of pockets configured to hold the balls. The plurality of pockets include at least two types of pockets including a first pocket and a second pocket. A gap on each of an outer circumferential surface side and an inner circumferential surface side of the cage between the ball and an inner circumferential surface of the second pocket is larger than a gap on each of the outer circumferential surface side and the inner circumferential surface side of the cage between the ball and an inner circumferential surface of the first pocket.

An air foil journal bearing can entirely restrain movement of a buffer member, which is provided inside a bearing housing in a direction of a shaft of the bearing. The air foil journal bearing includes: the bearing housing having a hollow part into which the shaft is inserted, wherein a first stopping groove is formed at an inner circumferential surface of the hollow part and a second stopping groove is formed at the inner circumferential surface of the hollow part along at least a part of an entire circumference of the hollow part; a top foil provided in the hollow part and configured to have a shape covering the shaft; and the buffer member provided between the hollow part and the top foil and elastically supporting the top foil.

There is provided a bearing device including: a tubular sleeve; a shaft held inside the sleeve; and a first bearing, a second bearing, a third bearing, and a fourth bearing, rotatably holding the shaft with respect to the sleeve and arranged in this order in an axial direction. An outer circumferential surface of an outer ring of each of the first to fourth bearings is fixed to an inner circumferential surface of the sleeve, a gap is provided between inner circumferential surfaces of inner rings of the second and third bearings and the shaft, and a spring applying a constant pre-load is provided between the inner rings of the second and third bearings.

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.

Aspects of the present disclosure include turbomachines designed and configured for high temperature and pressure operation and increased power level output that minimize pressure vessel design requirements, and increase dry gas seal reliability. In some examples, a first radial bearing is located in a high temperature and/or pressure region of the turbomachine between a rotor of the machine and a dry gas seal while other bearings are located outside of the high pressure region.

There is provided a bearing device including: a tubular sleeve; a shaft held inside the sleeve; and a first bearing, a second bearing, a third bearing, and a fourth bearing, rotatably holding the shaft with respect to the sleeve and arranged in this order in an axial direction. An outer circumferential surface of an outer ring of each of the first to fourth bearings is fixed to an inner circumferential surface of the sleeve, a gap is provided between inner circumferential surfaces of inner rings of the second and third bearings and the shaft, and a spring applying a constant pre-load is provided between the inner rings of the second and third bearings.

A hard disk drive includes a base deck that is coupled to a cover, a motor assembly that is coupled to the base deck, and magnetic recording media that is coupled to the motor assembly. The motor assembly includes a magnetic bearing with a horizontal magnetic bearing component and a vertical magnetic bearing component.

According to one embodiment, a disk device includes a 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 the rib and above the first cover. The rib includes a first region with a first chamfered surface with a first chamfered width and a second region with a second chamfered surface with a second chamfered width which is less than the first chamfered width. The first region and the second region are located corresponding to a side portion of the recording medium.

A pivot assembly bearing apparatus includes: a shaft extending in an axial direction, a first rolling bearing, a second rolling bearing and a first sleeve bonded to an outer peripheral surface of the first outer ring of the first rolling bearing, a second sleeve bonded to an outer peripheral surface of the second outer ring of the second rolling bearing and a spacer abutting on a lower end surface of the first outer ring and an upper end surface of the second outer ring. A part of the first sleeve protruding downwards in the axial direction from the first outer ring is bonded to the spacer, and a part of the second sleeve protruding upwards in the axial direction from the second outer ring is bonded to the spacer.