Abstract: In a hydrodynamic bearing device in which a radial bearing face having a dynamic pressure generating groove on a shaft or an inner periphery of a sleeve is provided and a clearance between the shaft and the sleeve is filled with lubricant, an annular depression is provided on one end face of the sleeve adjacent to a rotor hub and a cover plate for covering the depression is attached to the sleeve so as to define a reservoir for the lubricant or air for the purpose of preventing such a risk that absence of an oil film occurs in clearances of a bearing of the hydrodynamic bearing device due to outflow of oil upon forcing of the oil by air received into the bearing. A step portion is provided on the other end face of the sleeve such that the step portion and the reservoir are communicated with each other by a communication hole. During operation of the hydrodynamic bearing device, air in the hydrodynamic bearing device reaches the reservoir via the communication hole so as to be discharged from the reservoir.

Abstract: A set of radial dynamic pressure generating grooves constitute a radial bearing, and an entire width (L) of the radial dynamic pressure generating groove is reduced. A set of thrust dynamic pressure generating grooves constituting a thrust bearing are formed so that an area where a maximal thrust dynamic pressure is generated (diameter) is increased, and a bearing angle stiffness of the thrust bearing is increased. The thrust bearing having the high bearing angle stiffness shares a moment load applied to a shaft to thereby compensate for a bearing angle stiffness of the radial bearing whose bearing stiffness is small because an entire width of the radial bearing is small. Thus, a thin-shaped hydrodynamic bearing capable of withstanding a large moment load is obtained.

Abstract: An object of the present invention is to provide a hydrodynamic bearing device having a high reliability which can achieve miniaturization and reduction of weight and thickness, and a motor and a disc driving apparatus using the same. In the hydrodynamic bearing device according to the present invention, a sleeve through which a shaft penetrates has a first opposing surface substantially orthogonal to a central axis of the shaft at one end and has a second opposing surface at the other end. A thrust plate having a disc shape which is fixed near one end of the shaft or which is integrally formed with the shaft is positioned so as to oppose the first opposing surface of the sleeve. A seal plate positioned near the other end of the shaft is positioned with a gap to the second opposing surface of the sleeve.

Abstract: A downsized spindle motor of excellent abrasion and shock resistance is provided. A shaft is fit into a sleeve. A flange is fixed to an end of the shaft. A radial bearing is formed on faces of the shaft and the sleeve, which faces are opposite and close to each other. A face of the flange closely faces a face of a thrust plate, thereby forming a thrust bearing. Another face of the thrust plate is caulked with a tip of the sleeve. The tip of the sleeve and the thrust plate are fixed to each other by an adhesive. A tapering section is provided at an upper end of the sleeve.

Abstract: A downsized spindle motor having a longer bearing service life and enhanced shock resistance includes a flange 11, which bears an axial load of a shaft 8, and which is fixed to an end of shaft 8. Laser welded section 14 is provided at the fixed section between shaft 8 and flange 11. Rotor hub 50 is fixed to another end of shaft 8, and laser welded section 54 firmly bonds the two elements.

Abstract: A downsized spindle motor having a longer service life of a bearing and enhanced shock resistance is provided. Flange 11, which bears an axial load of shaft 8, is fixed to an end of shaft 8. Laser welded section 14 is provided to the fixed section between shaft 8 and flange 11. Rotor hub 50 is fixed to another end of shaft 8, and laser welded section 54 firmly bonds the two elements.

Abstract: A downsized spindle motor of excellent abrasion and shock resistance is provided. Shaft 8 is fit into sleeve 5. Flange 11 is fixed to an end of shaft 8. A radial bearing is formed on the faces of shaft 8 and sleeve 5, the faces are opposite closely to each other. Face 17 of flange closely faces face 16 of thrust plate 12, thereby forming a thrust bearing. The other face 22 of thrust plate 12 is caulked with tip 21 of sleeve 5 and fixed to each other by adhesive 27. Tapering section 6 is provided to an upper end of sleeve 5.

Abstract: Fluid bearing equipment which is free from lockup or seizure which may occur due to a deficiency of a lubricating fluid when the equipment is operated at a high rotation speed in a high temperature environment. The fluid bearing equipment is arranged such that maximum pressure generating portions 23 of dynamic pressure generating grooves 15, 16 provided in a thrust-side dynamic pressure generating portion are located closer to the outer circumference of a stationary thrust plate 9 than a radially middle position of the thrust-side dynamic pressure generating portion. With this arrangement, the lockup and seizure of a motor can be prevented which may otherwise occur due to a deficiency of the lubricating fluid when the equipment is operated at a high rotation speed in a high temperature environment.

Abstract: A bearing comprises a rotating shaft, a sleeve which surrounds the outer wall of the rotating shaft and supports the rotating shaft in such a manner that the rotating shaft is rotatable, and a thrust bearing plate which is fixed to the sleeve and supports one end of the rotating shaft. A first herringbone pattern and a second herringbone pattern are formed either on the rotating shaft or on the sleeve, wherein the first herringbone pattern is located at a first side and the second herringbone pattern is located at a second side, wherein the first side is the side where the thrust bearing plate is located, and the second side is the side opposite the first side. The relation between width-A and width-B in the first herringbone pattern is expressed by 0<(A−B)<0.

Abstract: A hydrodynamic bearing which prevents a lubricating fluid from scattering out of the dynamic pressure generating portion. The bearing includes radial spacing d of a gap at an open end of the thrust-side dynamic pressure generating portion, whose value is greater than a spacing of the thrust-side dynamic pressure generating portion, as measured relative to the thrust direction. Scattering of lubricating fluid from the open end of the thrust-side dynamic pressure generating portion is therefore prevented even when the bearing rotates at a high speed in a high temperature envivronent.

Abstract: An object of the present invention is to provide a hydrodynamic bearing device which has an improved construction to prevent a lubricating fluid from scattering out of a dynamic pressure generating portion. The hydrodynamic bearing device of the present invention is characterized in that a radial spacing &Dgr;d of a gap at an open end of a thrust-side dynamic pressure generating portion is set greater than a spacing 26 of the thrust-side dynamic pressure generating portion as measured with respect to the thrust direction. With this arrangement, the scattering of the lubricating fluid from the open end of the thrust-side dynamic pressure generating portion is prevented even when the hydrodynamic bearing device is operated at a high rotation speed in a high temperature environment.

Abstract: An object of the present invention is to provide a fluid bearing equipment which is free from lockup or seizure which may occur due to a deficiency of a lubricating fluid when the equipment is operated at a high rotation speed in a high temperature environment. The fluid bearing equipment is arranged such that maximum pressure generating portions 23 of dynamic pressure generating grooves 15, 16 provided in a thrust-side dynamic pressure generating portion are located closer to the outer circumference of a stationary thrust plate 9 than a radially middle position of the thrust-side dynamic pressure generating portion. With this arrangement, the lockup and seizure of a motor can be prevented which may otherwise occur due to a deficiency of the lubricating fluid when the equipment is operated at a high rotation speed in a high temperature environment.

Abstract: It is an object of the present invention to provide a hydrodynamic bearing which is highly reliable and capable of preventing a lubricant contained therein from flowing out of the bearing. In the hydrodynamic bearing, lower and upper end portions of a stationary shaft are properly spaced from a sleeve and a thrust plate, respectively, and an air channel is provided inside the stationary shaft with one end thereof opening to a space defined between an outer circumferential portion of the stationary shaft and the sleeve and with the other end thereof communicating with the outside. Thus, the hydrodynamic bearing has a highly reliable construction which can assuredly prevent the flow-out of the lubricant.

Abstract: It is an object of the present invention to provide a motor capable of reducing a loss as much as possible, and securing minimum vibration proof performance and reliability by definitely defining the upper and lower limits of a minimum shaft diameter in conformity with a disk load, the service number of revolutions or the like. In a shaft-fixed type motor of the fluid bearing specifications, the diameter d (mm) of a fixed shaft is set so as to satisfy the relation of &agr;3·M1 >d3>M1, where M1=J1·(N/1000)2·k2·D, J1 being a coefficient to be experimentally determined, N(rpm) the service number of revolutions, k the number of a disk-shaped recording media, D (inch) the diameter of the disk-shaped recording medium, and &agr; a ratio of the maximum diameter to the minimum diameter of the fixed shaft.

Abstract: A dynamic pressure type fluid bearing device includes a rotary shaft, a hollow sleeve in which the rotary shaft is rotatably mounted, and at least two sets of dynamic pressure generating grooves formed in either an outer surface of the rotary shaft or an inner surface of the sleeve. In this construction, a value obtained from k.times.sin .beta. is made equal to about 0.1 or ranges from 0.09 to 0.12, where k=d/e, d is a width of the dynamic pressure generating grooves, e is an interval between neighboring dynamic pressure generating grooves, and .beta. is an angle of the dynamic pressure generating grooves relative to a direction of rotation of the rotary shaft.

Abstract: A rotating polygon mirror driving apparatus has a rotor having a rotating polygon mirror fixed thereto, a rotational shaft and a rotor magnet; a bracket having a base plate provided opposite to the rotor magnet and a collar forming a bearing holding portion of a resin outserted to the base plate and made; and a bearing fitted to the bracket so as to support the rotational shaft. The driving apparatus can be decreased in cost and thickness while maintaining excellent rotational precision and mechanical precision.

Abstract: A rotating polygon mirror driving apparatus has a rotor having a rotating polygon mirror fixed thereto, a rotational shaft and a rotor magnet; a bracket having a base plate provided opposite to the rotor magnet and a collar forming a bearing holding portion of a resin outserted to the base plate and made; and a bearing fitted to the bracket so as to support the rotational shaft. The driving apparatus can be decreased in cost and thickness while maintaining excellent rotational precision and mechanical precision.