Abstract: There are provided a hydrodynamic bearing assembly and a motor including the same. The hydrodynamic bearing assembly includes a sleeve rotatably supporting a shaft and including a first circulation hole formed therein, the first circulation hole penetrating between an inner peripheral surface thereof and an outer peripheral surface thereof; a sleeve housing into which the sleeve is inserted; and a second circulation hole formed between the outer peripheral surface of the sleeve and an inner peripheral surface of the sleeve housing to be in communication with the first circulation hole, wherein an upper portion of the second circulation hole has a larger diameter than a lower portion thereof in an axial direction.

Abstract: There are provided a spindle motor and a hard disk drive including the same, the spindle motor including: a lower thrust member fixedly attached to a base member; a shaft fixedly attached to the lower thrust member and including an expansion groove formed in an outer peripheral surface thereof in a circumferential direction; a sleeve disposed above the lower thrust member and rotatably attached to the shaft; and a rotor hub coupled to the sleeve and rotating together therewith, wherein the lower thrust member includes a fitting protrusion protruded upwardly from an inner portion thereof in an axial direction and press-fitted into a fixing groove provided in a lower end portion of the shaft upwardly in the axial direction.

Abstract: There is provided a hydrodynamic bearing assembly including a sleeve; and a shaft rotatably inserted into a shaft hole and constituting a bearing clearance, wherein at least one of an inner circumferential surface of the sleeve and an outer circumferential surface of the shaft includes upper and lower radial dynamic pressure grooves having a herringbone pattern, and conditional expressions a+b>c+d and b?a>c?d>0 are satisfied.

Abstract: There are provided a hydrodynamic bearing assembly and a motor including the same. The hydrodynamic bearing assembly includes a sleeve rotatably supporting a shaft and including a first circulation hole formed therein, the first circulation hole penetrating between an inner peripheral surface thereof and an outer peripheral surface thereof; a sleeve housing into which the sleeve is inserted; and a second circulation hole formed between the outer peripheral surface of the sleeve and an inner peripheral surface of the sleeve housing to be in communication with the first circulation hole, wherein an upper portion of the second circulation hole has a larger diameter than a lower portion thereof in an axial direction.

Abstract: There is provided a hydrodynamic bearing assembly including a sleeve; and a shaft rotatably inserted into a shaft hole and constituting a bearing clearance, wherein at least one of an inner circumferential surface of the sleeve and an outer circumferential surface of the shaft includes upper and lower radial dynamic pressure grooves having a herringbone pattern, and conditional expressions a+b>c+d and b?a>c?d>0 are satisfied.

Abstract: There are provided a spindle motor and a hard disk drive including the same, the spindle motor includes: a shaft fixedly installed on a base member and including an upper thrust member provided in an upper portion thereof and protruded outwardly in a radial direction, a sleeve supported by fluid dynamic pressure so as to be rotatable with respect to the shaft, a hub extended from the sleeve outwardly in the radial direction, and a sealing cap mounted on the hub and extended to an upper portion of the upper thrust member so as to cover a space between the upper thrust member and the hub formed in the axial direction.

Abstract: There is provided a spindle motor including: a shaft having a lower end portion fixed to one of a base member and a lower thrust member and provided with an installation groove depressed downwardly from an upper surface thereof; an upper thrust member including an insertion part inserted into and fixed to the installation groove of the shaft; and a rotating part forming a bearing clearance together with the upper and lower thrust members and the shaft and rotating around the shaft.

Abstract: There are provided a spindle motor and a hard disk drive including the same, the spindle motor including: a lower thrust member fixedly attached to a base member; a shaft fixedly attached to the lower thrust member and including an expansion groove formed in an outer peripheral surface thereof in a circumferential direction; a sleeve disposed above the lower thrust member and rotatably attached to the shaft; and a rotor hub coupled to the sleeve and rotating together therewith, wherein the lower thrust member includes a fitting protrusion protruded upwardly from an inner portion thereof in an axial direction and press-fitted into a fixing groove provided in a lower end portion of the shaft upwardly in the axial direction.

Abstract: A spindle motor includes a base part including a base member and a lower thrust member fixed to the base member; a shaft having a lower end portion fixed to the base part and including a sealing groove formed in an outer peripheral surface thereof to form a liquid-vapor interface; an upper thrust member fixed to an upper end portion of the shaft; a rotating member including a sleeve part between the upper and lower thrust members; and an upper case fixing the upper end portion of the shaft. The shaft includes a connection groove recessed downwardly from an upper surface thereof and a communication hole for connecting the connection groove to the sealing groove. At least one of the shaft and a lower surface of the upper case has a connection part for connecting the connection groove to a space between the upper case and the upper thrust member.

Abstract: A bearing assembly for use in an electric motor minimizes the generation of a negative pressure. In the bearing assembly, gaps are formed between a shaft provided with a flange portion, a ring member mounted on the shaft, and a sleeve member with a through hole formed therein are continuously filled with lubrication oil. When a rotor rotates, the rotor is supported by a fluid dynamic pressure. In the bearing assembly, herringbone grooves are formed in an upper surface of the flange portion of the shaft fixed to a base plate. When the sleeve member rotates with respect to the shaft, ends of all of the herringbone grooves and the through hole are superposed on each other sequentially. Thus, the lubrication oil can be efficiently supplied to an outer peripheral region in the thrust dynamic pressure bearing mechanism in which the negative pressure is most prone to be generated, and generation of the negative pressure can be efficiently minimized.

Abstract: An oil dynamic bearing, a motor and a disk drive adapted to be reduced in both size and thickness are disclosed. The oil dynamic bearing (B) includes at least two bearing portions (B1, B2), each having a bearing near end nearer to the rotational axis or the bearing center of the bearing and a bearing far end farther from the rotational axis or the bearing center of the bearing. The near and bearing far ends are each connected to a taper seal portion, which in turn communicates with the atmosphere. The taper seal portion connected to the bearing near end of the bearing portion (B1) and the taper seal portion connected to the bearing near end of the other bearing portion (B2) make up a common taper seal portion.

Abstract: A bearing assembly for use in an electric motor minimizes the generation of a negative pressure. In the bearing assembly, gaps are formed between a shaft provided with a flange portion, a ring member mounted on the shaft, and a sleeve member with a through hole formed therein are continuously filled with lubrication oil. When a rotor rotates, the rotor is supported by a fluid dynamic pressure. In the bearing assembly, herringbone grooves are formed in an upper surface of the flange portion of the shaft fixed to a base plate. When the sleeve member rotates with respect to the shaft, ends of all of the herringbone grooves and the through hole are superposed on each other sequentially. Thus, the lubrication oil can be efficiently supplied to an outer peripheral region in the thrust dynamic pressure bearing mechanism in which the negative pressure is most prone to be generated, and generation of the negative pressure can be efficiently minimized.

Abstract: A spindle motor and a compact, thin recording disk driving apparatus consuming less power and capable of stable rotation are disclosed. A magnetic head, when accessing a recording disk, is pressed against the recording disk and generates a moment to tilt the rotational axis in a specified direction. A mechanism to constantly apply a bias moment in the opposite direction to the tilt reduces the maximum load moment and makes it possible to avoid the bearing damage while at the same time suppressing the bearing loss considerably.

Abstract: An oil dynamic bearing, a motor and a disk drive adapted to be reduced in both size and thickness are disclosed. The oil dynamic bearing (B) includes at least two bearing portions (B1, B2), each having a bearing near end nearer to the rotational axis or the bearing center of the bearing and a bearing far end farther from the rotational axis or the bearing center of the bearing. The near and bearing far ends are each connected to a taper seal portion, which in turn communicates with the atmosphere. The taper seal portion connected to the bearing near end of the bearing portion (B1) and the taper seal portion connected to the bearing near end of the other bearing portion (B2) make up a common taper seal portion.