The preset invention aims to improve the assembly accuracy and rotation accuracy of a fluid bearing device, and to further reduce the cost thereof. A bearing sleeve is fixed on the inner periphery of a housing. An axial member is supported in a non-contact manner in a radial direction by an oil film formed in a radial bearing gap. The housing made of resin is injection molded with the use of a substrate as an insert part. On the substrate, a control circuit for controlling a polygon scanner motor is mounted.

Fluid bearing device

A fluid dynamic bearing device which exhibits high bearing performance at low cost has a highly accurate bearing gap. At least a region in the outer circumferential surface of a shaft, which faces the radial bearing gap, is constituted of an electroformed part, and the region of the shaft excluding the electroformed part is constituted of a resin portion.

Fluid dynamic bearing device

A fluid bearing device achieves superior in wear resistance in starting and stopping and in manufacturing ability The fluid bearing device includes a shaft having a flange portion, a sleeve opposing to the shaft across a fluid bearing clearance of a radial fluid bearing, a counterpart member opposing to at least one of plane of the flange portion across a fluid bearing clearance of a thrust bearing The flange portion and the sleeve portion being formed of copper alloy of mutually difference composition

Low-profile spindle motor whose entire shaft length is utilized to configure, along an encompassing sleeve, a radial dynamic-pressure bearing section. One end of the shaft is unitary with the rotor, and a cover member closes the other end. Between the sleeve upper-end face and the rotor undersurface a thrust bearing section is configured. Micro-gaps are formed continuing between the sleeve upper-end face and the rotor undersurface; the sleeve inner-circumferential surface and the shaft outer-circumferential surface; and the cover member inner face and the shaft end face, where an axial support section is established. Oil continuously fills the micro-gaps without interruption, configuring a fully filled hydrodynamic bearing structure. Hydrodynamic pressure-generating grooves in the radial bearing section are configured so that no axial flow is induced in the oil, and in the thrust bearing so that lift pressure, balanced by hydrostatic pressure in the axial support section, is imparted in the oil.

Spindle motor, and disk drive utilizing the spindle motor

In a spindle motor utilizing dynamic-pressure bearings having a full-fill structure, a bearing configuration that balances and sustains at or above atmospheric pressure the internal pressure of the bearing oil. Thrust and radial bearing sections are configured within oil-filled bearing clearances in between the rotor, the shaft, and a shaft-encompassing hollow bearing member. A communicating passage one end of which opens on, radially inwardly along, the thrust bearing section is formed in the bearing member. Either axial ends of the bearing clearance in between the bearing member and shaft communicate through the passage. The communicating passage enables the oil to redistribute itself within the bearing clearances. Pressure difference between the axial upper and lower ends of the oil retained in between the bearing member and the shaft is compensated through the communicating passage, preventing incidents of negative pressure within the oil and of over-lift on the rotor.

Spindle motor and disk drive furnished therewith

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)<0.2x(A+B), where A denotes the dimension from a turning point of the first herringbone pattern to the end thereof in the first side, and B denotes the dimension from the turning point to the end thereof in the second side, and, the relation between width-C and width-D in the second herringbone pattern is expressed by 0 ((D(C) (0.2((D+C), where C denotes the dimension from a turning point of the second herringbone pattern to the end thereof in the first side, and D denotes the dimension from the turning point to the end thereof in the second side. The above structure enables the reduction of the radial runout of the rotating shaft of the bearing and the improvement of the durability of the bearing.

Hydrodynamic bearing and motor having the same

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.

Hydrodynamic bearing device and disk rotating apparatus

A hydrodynamic bearing device with high reliability, with which reductions in size, weight, and thickness can be achieved, as well as a motor and a disk driving apparatus that make use of this hydrodynamic bearing device. The hydrodynamic bearing device comprises a shaft, a thrust flange, a sleeve, a seal plate, and a retaining plate. A radial dynamic pressure bearing is formed in the radial direction gap between the shaft and the sleeve, and a thrust dynamic pressure bearing is formed in the thrust dynamic bearing gap between the sleeve and the thrust flange. A communicating hole is formed for communicating between the gap between the sleeve and the seal plate and the thrust direction gap between the sleeve and the thrust flange. The radial dynamic pressure bearing and/or the thrust dynamic pressure bearing are formed such that a lubricating oil circulates in the gap between the sleeve and the seal plate from the inner peripheral side of the sleeve toward the outer peripheral side.

Hydrodynamic bearing device, motor, and disk driving apparatus

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.

Spindle motor and method for assembling the same

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.

Takao Yoshitsugu

Papers

Hydrodynamic bearing and motor having the same

Hydrodynamic bearing device and disk rotating apparatus

Hydrodynamic bearing device, motor, and disk driving apparatus

Spindle motor and method for assembling the same

Hydrodynamic bearing device