Nidec Corporation

Nippon Densan Corporation

Yoshito Oku

Hideki Nishimura

Hiroyuki Yonei

Nobuaki Watanabe

Shinya Yano

Tokichi Ito

Shigeharu Sumi

Kaoru Uenosono

Shinya Tokunaga

Hiromasa Fujii

Shinobu Hattori

Yusuke Matsumoto

Susumu Terada

Yasuhiro Higuchi

Shozo Ibara

A fluid dynamic-pressure bearing includes a rotatable shaft, a hub, a fixed portion, and a lubricating liquid. The hub includes a hub thrust bearing surface extending from the shaft outwardly in a radial direction and an annular surface. The fixed portion includes a fixed-portion upper thrust bearing surface facing the hub thrust surface and a flange surface facing the annular surface. The hub thrust bearing surface, the fixed-portion upper thrust bearing surface, and the lubricating liquid arranged therebetween form together an upper thrust dynamic-pressure bearing. The annular surface and the flange surface define an annular gap therebetween. An axial dimension of the annular gap is larger than a total of an axial dimension of an upper thrust gap between the hub thrust bearing surface and the fixed-portion upper thrust bearing surface and an average depth of upper thrust dynamic-pressure generating grooves of the upper thrust dynamic-pressure bearing.

Fluid dynamic-pressure bearing device and spindle motor

Small-size, small-height fluid dynamic-pressure bearing device that causes a low shaft loss and is less prone to troubles such as shortage and leakage of lubricating liquid. A thrust dynamic-pressure bearing is formed at an inner position and a region having a slightly-widened gap is provided outside of the thrust dynamic-pressure bearing to retain the lubricating liquid therein. Further, an oil circulating path is communicated with the region having a slightly widened gap. The gap of this region is set to be greater than the gap at the thrust dynamic-pressure bearing portion by the value of the depth of dynamic-pressure generating grooves. The region having a widened gap may be provided with rows of grooves for stirring-up lubricating oil towards the center.

The present invention provides a method for sealing a metal housing member. A housing through hole is formed in a housing member for a lead wire sealing device. The housing member is provided with a housing through hole formed on the metal housing member and penetrates from a closed space to an open space. A resin coating layer is formed to cover a lower surface of the housing member. A metal surface exposed part is formed on a part of the resin coating layer. The circuit board having a board aperture is mounted on the metal surface exposed part via an adhesive layer while overlapping with the board aperture on the housing through hole. The lead wire is inserted in the housing through hole and the board aperture that are overlapped with each other. The sealing material is provided on the circuit board to cover the board aperture.

Sealing method for through hole formed in metal housing

A first metal housing memberis provided with a bottom plate partand a resin coating layerformed on a lower surface of the bottom plate part. To a board mounted partwhich is a metal surface exposed part exposed from the resin coating layeraround a housing through hole, an FPCis mounted via an adhesive layer. A lead wireof a stator windingsthat is inserted in a board apertureis connected to the FPCby a sealing materialas a solder and the board apertureis covered with the sealing materialto seal the housing through hole. A motor unitcan securely seal the housing through holeby enhancing adhesiveness between the FPCand the first metal housing member

Lead wire sealing device, recording disk drive, and method for sealing housing member

The present invention relates to a hydrodynamic bearing supporting a shaft and a sleeve so as to relatively rotate with respect to a rotation axis. In accordance with one example of the present invention, there is provided a hydrodynamic bearing in which a capillary seal portion is formed continuously in a bearing portion having a lubricating oil retained in a micro gap as a working fluid. The capillary seal portion is provided with a first capillary seal portion having a first radial gap, a dimension of the first radial gap being getting at least wider in accordance with increasing a distance from the bearing portion in the rotation axis, and a second capillary seal portion adjoining the first capillary seal portion and having a second radial gap, a dimension of the second radial gap being getting at least wider in accordance with increasing a distance from the bearing portion in the rotation axis. The second capillary seal portion is expanded progressively in accordance with getting toward an outer side in an axial direction.

Hydrodynamic bearing, spindle motor using the same and disc drive apparatus provided with 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

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, configuring a full-fill hydrodynamic bearing structure. Hydrodynamic pressure-generating grooves in the radial bearing section are configured either so that no axial flow, or so that a unidirectional flow that recirculates from one to the other axial end of the radial bearing section through a communicating pathway is induced in the oil.

Spindle motor and disk drive utilizing the spindle motor

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.

Oil-retaining configuration in partially filled or fully filled dynamic-pressure bearing system for miniaturized, low-profile spindle motor. A radial bearing section and a magnetically balanced thrust bearing section compose the bearing system. An oil taper seal is configured in between the rotor and the sleeve, radially beyond the radial bearing section, and not axially beyond the thrust bearing section. The taper-seal gap slopes radially inward, flaring with further separation from the rotor undersurface, in a configuration that lengthens the tapered space functioning as, and enlarges the capacity within, the taper-seal area, and that sets up the oil boundary surface oriented sloping radially inward. Centrifugal force during rotation thus acts pressing in on the oil boundary surface, fortifying the sealing strength. The oil-retaining configuration allows for span, between twin constituents provided as the radial bearing section, sufficient for increased conical stiffness even in a reduced-profile structure.

Spindle motor, and disk drive utilizing the spindle motor

A spindle motor comprises a stationary member having a round mounting hole therein, a tubular member fitted into the mounting hole of the stationary member, a bearing means mounted to the inner side of the tubular member, a rotor supported by the bearing means for rotation in relation to the tubular member, a stator fitted onto the outer side of the tubular member, and a rotor magnet mounted to the rotor to be located radially and outwardly of the stator. The procedure of assembling the spindle motor includes mounting the rotor magnet to the rotor, joining the rotor by the bearing means to the tubular member for rotation, fitting the stator onto the tubular member, and fitting the tubular member into the mounting hole of the stationary member.

Spindle motor design facilitating and ensuring precise assembly of the

A spindle motor comprises a stationary member having a cylindrical mounting hole therein, a tubular member fitted into the mounting hole of the stationary member, a bearing means mounted to the inner side of the tubular member, a rotor supported by the bearing means for rotation in relation to the tubular member, a stator fitted onto the outer side of the tubular member, and a rotor magnet mounted to the rotor to be located radially and outwardly of the stator. The procedure of assembling the spindle motor includes mounting the rotor magnet to the rotor, joining the rotor by the bearing means to the tubular member for rotation, fitting the stator onto the tubular member, and fitting the tubular member into the mounting hole of the stationary member.

Spindle motor

A motor having a bracket with a stator coil for generating a magnetic field and a rotor hub with rotor magnets for receiving a rotation force from the magnetic field generated by the coil. Upper and lower dynamic pressure radial bearings are formed in between the sleeve and the rotary shaft. The lower end surface of the rotary shaft is formed with a spiral groove in which a lubricating fluid is filled to form a dynamic pressure thrust bearing. The spiral groove is formed by a circular hole at the center of the shaft, and a plurality of curved grooves each curving from the circular hole to the direction opposite to the rotation direction of the shaft and gradually increasing its width toward the outer circumference of the lower end surface of the shaft without reaching the circumference. The spiral groove functions to move the lubricating fluid outward in the radial direction from the center of the shaft, when the shaft rotates.

A spindle motor comprises a rotary sleeve; a rotor hub which is integrally rotated with the rotary sleeve; a stationary sleeve; and a stationary support extending upwardly from the stationary part, the rotary sleeve being fitted onto the outer peripheral surface of the stationary support, and radial and thrust hydrodynamic bearings being provided on the relative sliding surfaces of both rotary sleeve and stationary support. A pair of annular grooves which partially overlap each other in the axial direction are peripherally provided on the rotary sleeve and stationary support, thereby providing a labyrinth chamber to suppress the outflow of the lubricant.

Low profile hydrodynamic motor having minimum leakage properties

A spindle motor comprises a central shaft, a hub rotatable about the shaft and having a central bore which is open at one end, a first bearing fitted in the bore to surround the shaft, a second bearing disposed within the bore to surround the shaft and axially spaced from the first bearing to be positioned closer to the open end of the bore, and an auxiliary bush fitted in the bore to fittingly receive the second bearing. The bush has an inward flange axially interposed between the first and second bearings. The flange provides a first surface in face-to-face contact with an outer race of the first bearing. The flange further provides a second surface parallel to the first surface and in face-to-face contact with an outer race of the second bearing.

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Kyoto, Japan

Yoshito Oku