Abstract: A double seal bearing includes a labyrinth seal mechanism. The double seal bearing is provided with a pair of annular inner and outer sealing plates having respective central openings with a remaining slight clearance between each respective sealing plate and one of the inner and outer races, respectively, so as to assure the labyrinth seal function.

Abstract: A bearing apparatus including inner and outer rings and balls interposed therebetween, the apparatus being characterized in that it comprises: a low expansion ring press fit around the outer periphery of the outer ring, wherein the low expansion ring is made of a material with lower factor of linear thermal expansion than the outer ring material.

Abstract: A compound bearing apparatus including a shaft, a cylindrical outer ring member surrounding the shaft, and a plurality of balls of the first and the second rows interposed between the shaft and the outer ring member is provided. The bearing apparatus of the present invention is characterized in that: the outer ring member includes upper and lower portions and a central portion therebetween, two rows of outer raceways for the first and the second row of balls are formed on the inner peripheral surface of the upper and lower portions of the outer ring member, a squeeze ring of the same material as that used in making the outer ring member or of any other material of substantially the same factor of linear thermal expansion as that of the outer ring member is press fit around the outer periphery of the central portion of the outer ring member to elastically deform the outer ring member inwardly to form an inwardly protruding squeezed portion.

Abstract: The object of the present invention is to provide a compound bearing apparatus having arrangements for preventing the lubricant present around the rotating bodies from leaking out to the outside as well as the interior space between two rows of rotating bodies of the bearing apparatus. This is effected for the purpose of providing the compound bearing apparatus and a spindle motor and a swing arm assembly for a hard disk drive device including such bearing apparatus in which the sufficient amount of lubricant can be retained around the rotating bodies to obtain long life feature and having substantially no noise or vibration due to the loss of lubricant.

Abstract: A shaft secured to a hub is inserted and rotatably supported in a sleeve secured to a base. A dynamic pressure groove is formed in the inner peripheral surface of the sleeve, and lubricant is sealed between the shaft and the sleeve. The rotation of the shaft causes dynamic pressure to generate in the lubricant due to the dynamic pressure groove, supporting the shaft floatingly. The ceramic sleeve allows heat generated in a coil to be hardly transferred to the shaft, thereby reducing the variations in the clearance between the shaft and the sleeve due to temperature changes to a minimum in cooperation with the ceramics sleeve with a low thermal expansion coefficient. Consequently, the rotation accuracy can be improved and the leakage of lubricant due to the variations in the clearance can be prevented.

Abstract: A shaft secured to a hub is inserted and rotatably supported in a sleeve secured to a base. A dynamic pressure groove is formed in the inner peripheral surface of the sleeve, and lubricant is sealed between the shaft and the sleeve. The rotation of the shaft causes dynamic pressure to generate in the lubricant due to the dynamic pressure groove, supporting the shaft floatingly. The crystallized-glass sleeve allows heat generated in a coil to be hardly transferred to the shaft, thereby reducing the variations in the clearance between the shaft and the sleeve due to temperature changes to a minimum in cooperation with the crystallized-glass sleeve with a low thermal expansion coefficient. Finishing accuracy of the bearing surface can be improved by chemical polishing. Consequently, the rotation accuracy can be improved and the leakage of lubricant due to the variations in the clearance can be prevented.

Abstract: A porous material suitable for use in a bearing rolling element. The porous material is obtained by a process which includes mixing degreased bran derived from rice bran with a thermosetting resin before kneading, subjecting a kneaded mixture to a primary firing in an inert gas at a temperature in a range of 700 to 100° C., pulverizing the kneaded mixture after the primary firing into carbonized powders sieved through a screen of 100-mesh, mixing the carbonized powders or the carbonized powders and ceramic powders with a thermosetting resin before kneading, pressure-forming a kneaded mixture thus obtained at a pressure in a range of 20 to 30 MPa, and applying a heat treatment again to a formed kneaded mixture in the inert gas at a temperature in a range of 100 to 1100° C.

Abstract: A spindle motor of the present invention is capable of keeping its ball (5a, 5b)'s pre-load constant, because a sleeve (6) is capable of being resiliently deformed due to its resiliency, and therefore capable of constantly keeping a pre-load applied to the balls (5a, 5b) from inner and inner ring raceways of inner and outer rings (3a, 4a, 3b, 4b) of ball bearings (3, 4). In this motor, a rotor hub (7) has an axial center bore (8). This bore (8) is provided with: a large-diameter bore portions in its opposite axial ends; and, a small-diameter bore portion (8a) axially interposed between the large-diameter bore portions. An inner diameter of the small-diameter bore portion (8a) is smaller than an outer diameter of the sleeve (6).

Abstract: In a method for manufacturing outer and inner rings of a bearing, the method being characterized in that it comprises the steps of: cutting a cylindrical bar material to form a circular plate work of a predetermined width, forming on both plain sides surface of the work through cold forging operation a central circular recess provided around the axis of the work and an annular groove provided concentrically with respect to the recess, forming a central circular aperture by punching out the recess remaining material in the axial direction, punching out the groove remaining material in the axial direction to form an outer work for the outer ring and an inner work for the inner ring, and machining each work respectively through cutting, grinding and/or polishing operations to form ring raceways or to finish the surface thereof for manufacturing the outer and inner rings.

Abstract: A spindle motor comprising a double row bearing device including a shaft, a sleeve surrounding the shaft, and a pair of upper and lower rows of balls, a cylindrical bearing holder extending upwardly from a base of the spindle motor for accommodating the sleeve within a vertical bore of the holder, and a rotor hub mounted on the shaft for journaling the rotor hub rotatably on the base, the spindle motor is characterized in that a reduced inner diameter portion of an inner diameter smaller than the outer diameter of the sleeve is formed on the inner surface of the bore of the bearing holder between the upper and lower larger inner diameter portions to urge the sleeve inwardly by the reduced inner diameter portion to deform it elastically to form a squeezed portion protruding inwardly of the sleeve between the upper and lower rows of balls.

Abstract: The object of the present invention is to provide a hard disk drive device having a bearing device of larger size and sufficient strength, improved impact resistance, high accuracy of rotation, and high reliability.

Abstract: A plurality of toroidal sealing plates 16a, 16b, and 16c spaced axially by slight gaps S1 and S2 are disposed between spindle 3 and vertical bore 6 of the rotor hub at above and/or below the bearing apparatus such that the outer or inner peripheral portion of each plate is secured to the inner peripheral portion of the bore of the rotor hub or the outer peripheral portion of the spindle so as to leave slight radial gaps &agr;1, &agr;2 and &agr;3 between the inner or outer peripheral portion of each plate and the outer peripheral portion of the spindle or the inner peripheral portion of the bore of the rotor hub to make each sealing plate uncontacted with the spindle or the bore, wherein the radial gaps are positioned alternately on the side of the spindle or on the side of the bore of the rotor hub.

Abstract: The object of the present invention is to provide a hard disk drive device having a bearing means of larger size and sufficient strength, improved impact resistance, high accuracy of rotation, and high reliability,

Abstract: A grinding operation is effected by rotating the motor hub in high speed around the central axis thereof, and urging the outer peripheral surface of a grinding wheel rotated in high speed around the central axis against the upper surface of the outwardly extending flange for supporting on its upper surface the lower surface of the central portion of the magnetic disk. The surface of the flange can be worked in high precision. Thus, a compact, large capacity, and reliable hard disk drive apparatus is to be provided by reducing the rotational runout of the magnetic disk incorporated within the hard disk drive apparatus.

Abstract: The inner ring 2 and the outer ring 3 of the roller bearing 1 as element are formed with silicate glass such as a high silicate glass, a soda-lime glass, alminosilicate glass, borosilicate glass and an alkali silicate glass, during its manufacturing processes a heat treatment is carried out for making the silicate glass polycrystalized and the thermal expansion coefficient of the inner ring 2 and the outer ring 3 diminished to prevent them from being changed minutely in dimension and the hardness and the strength of the rolling surfaces 2a, 3a increased to diminish the revolution vibration and the revolution noise due to the revolution vibration and prevent the impact due to miniaturization of the apparatus from being generated.

Abstract: The object of the present invention is to provide a blower including a bearing structure wherein the number of components is reduced, the cost for manufacturing can be reduced, and the diameter of the shaft can be increased. The bearing structure is good at its durability, eliminates or reduces the rotational run out, and provides superior quietness.

Abstract: A spindle motor of the present invention is capable of keeping its ball (5a, 5b)'s pre-load constant, because a sleeve (6) is capable of being resiliently deformed due to its resiliency, and therefore capable of constantly keeping a pre-load applied to the balls (5a, 5b) from inner and inner ring raceways of inner and outer rings (3a, 4a, 3b, 4b) of ball bearings (3, 4). In this motor, a rotor hub (7) has an axial center bore (8). This bore (8) is provided with: a large-diameter bore portions in its opposite axial ends; and, a small-diameter bore portion (8a) axially interposed between the large-diameter bore portions. An inner diameter of the small-diameter bore portion (8a) is smaller than an outer diameter of the sleeve (6).

Abstract: A motor that can prevent damages on the fluid dynamic bearing. A ball is press-fitted into the end surface of the shaft body, and the ball is disposed in such a manner that the tip portion of the ball comes to the higher position with respect to the end surface of the annular body. When the shaft is at rest, the ball abuts against the upper surface of the counter plate, and the end surface of the annular body is brought into a state of being raised from the upper surface of the counter plate, so that the situation in which the end surface of the annular body and the upper surface of the counter plate are brought into almost fully touch each other can be avoided. Therefore, when the operation is started, the circulation speed of a fluid increases and a fluid layer is quickly formed. As a consequent, the fluid circularity blocking action, which could be occurred in the relate art, is avoided, and generation of scratch caused by starting rotation in the tightly sticked state can be positively prevented.

Abstract: An anti-friction bearing is provided which is low in vibration and excellent in quietness. The anti-friction bearing has rolling elements provided in inner and outer ring raceway grooves, which are made of martensitic stainless steel composed of 0.60 to 0.75 percent of carbon by weight, 10.5 to 13.5 percent of chromium by weight, 1.0 percent or less of silicon by weight and 0.3 to 0.8 percent of manganese by weight, the remainder of the composition being iron and inevitably introduced impurities, having a hardness of HRC 58 or higher, containing eutectic carbide particles of 10 microns or less in diameter, having oxygen and titanium concentrations of 10 ppm or less respectively, and less than 10 percent by volume of retained austenite.

Abstract: A tile comprises a fire resistant ceramic, which is obtained by mixing and kneading defatted bran obtained from rice bran and a thermosetting resin, primarily baking the resulting mixture in an inert gas at 700° C. to 1000° C., crushing the resulting product into carbonized powder, mixing and kneading the carbonized powder with a ceramic powder, a solvent and, optionally, a binder to provide a plasticized mixture (ceramic-solvent mixture), pressure forming the mixture at a compression pressure of 10 MPa to 100 MPa, and heat treating the resulting compact again in an atmosphere of an inert gas at 500 to 1400° C.