Abstract: The opening of an oil container 11 for storing oil 12 is sealed airtight with a cover member 32. A one-sided-bag-shaped fluid dynamic pressure bearing 10 is seated on an O-ring 25 and fixed airtight onto the upper surface of a bearing seating 30. Inanexhaust position with the distal end portion of an injection tube 36 positioned away from an oil level, the inside of the oil container 11 is evacuated by a vacuum pump 22 through a suction/exhaust passage including a suction/exhaust through-hole 17, thus turning the inside of the one-sided-bag-shaped fluid dynamic pressure bearing (10) into a vacuum. In this state, a control device drives a moving device to raise the oil container 11 to an injection position and releases the suction/exhaust passage to the atmosphere. This causes the oil 12 to be injected into the one-sided-bag-shaped fluid dynamic pressure bearing 10 through an oil injection passage including the injection tube 36.

Abstract: The opening of an oil container 11 for storing oil 12 is sealed airtight with a cover member 32. A one-sided-bag-shaped fluid dynamic pressure bearing 10 is seated on an O-ring 25 and fixed airtight onto the upper surface of a bearing seating 30. Inanexhaust position with the distal end portion of an injection tube 36 positioned away from an oil level, the inside of the oil container 11 is evacuated by a vacuum pump 22 through a suction/exhaust passage including a suction/exhaust through-hole 17, thus turning the inside of the one-sided-bag-shaped fluid dynamic pressure bearing (10) into a vacuum. In this state, a control device drives a moving device to raise the oil container 11 to an injection position and releases the suction/exhaust passage to the atmosphere. This causes the oil 12 to be injected into the one-sided-bag-shaped fluid dynamic pressure bearing 10 through an oil injection passage including the injection tube 36.

Abstract: In a hydraulic bearing motor, by means of dynamic pressure generating grooves provided on a thrust shaft with a larger diameter not only on the end face thereof but also on the shaft surface thereof, pressures generated in oil when rotating a shaft body are made to be applied not only in the axial direction but also in the radial direction with high magnitude. This can provide the hydraulic bearing motor as being capable of satisfying features of exhibiting small NRRO, and vibration and shock resistance even with a thinned hydraulic bearing motor.

Abstract: A hydraulic dynamic pressure bearing motor has a rotational shaft mounted to undergo rotation about a rotational axis and having a shaft section and a flange section. A sleeve has a cavity for receiving the rotational shaft. A cover member is disposed over an open end of the sleeve cavity. A hydraulic dynamic pressure bearing includes minute radial and thrust clearances disposed between outer surface portions of the shaft and flange sections of the rotational shaft and inner surface portions of the sleeve and the cover member. A lubricating fluid is disposed in the minute radial and thrust clearances. The minute radial and thrust clearances are dimensioned so that during a non-rotational state of the rotational shaft, the flange section of the rotational shaft contacts preselected inner surface portions of the sleeve and the cover member while the shaft section of the rotational shaft does not contact any portion of the sleeve and an inner peripheral surface of the cover member.

Abstract: In a spindle motor, a core with a specified thickness is formed by laminating thinnest possible magnetic steel sheets to allow consumed current to be reduced. For example, by providing a structure of a core of a spindle motor with seven 0.2 mm thick steel sheets being laminated, it becomes possible to make consumed current smaller than that for a core laminated with four 0.35 mm thick steel sheets. Thus, a spindle motor is provided as being suited for downsizing an HDD and possible to reduce consumed power.

Abstract: In a thin dynamic pressure hydraulic bearing motor used for a compact HDD device which motor is provided with a thin hydraulic dynamic pressure bearing comprising a flanged rotary shaft comprising a shaft and a flange, a sleeve into which the flanged rotary shaft is rotatably inserted, a ring-like lid 35, and lubricating oil filling minute clearances formed by those bearing components, the thrust clearance c is determined as being equal to or less than a value for which a product md of the maximum vertical shift m at a rim of a magnetic disk and a diameter d of the flange of the flanged rotary shaft is divided by 4r, four times a radius r of the magnetic disk. Thus, even when no bearing stiffness is provided for the hydraulic dynamic pressure bearing motor at rest, the magnetic disk is made so as not to contact with a head supporting system such as a head loading arm.

Abstract: In a hydraulic bearing motor, by means of dynamic pressure generating grooves provided on a thrust shaft with a larger diameter not only on the end face thereof but also on the shaft surface thereof, pressures generated in oil when rotating a shaft body are made to be applied not only in the axial direction but also in the radial direction with high magnitude. This can provide the hydraulic bearing motor as being capable of satisfying features of exhibiting small NRRO, and vibration and shock resistance even with a thinned hydraulic bearing motor.

Abstract: A method for lubricating a part without leaving air bubbles includes the steps of assembling components so that an open end is formed for application of lubricating fluid and a fluid path is provided through which the lubricating fluid is to be circulated, introducing the lubricating fluid into the open end and applying a centrifugal force to the component by moving the component about a circular path so that the centrifugal force causes the lubricating fluid to be urged throughout the fluid path. The method is used in an embodiment to lubricate a dynamic pressure bearing having a gap between relatively moving parts. The gap has an open end into which the lubrication fluid is dripped and a closed end. During movement of the bearing about a circular path, the fluid is urged from the open end to the closed end.