Minebea Kabushiki-kaisha

Minebea Company, Limited

Minebea Kabushiki-kaisha (minebea Co., Ltd.)

Rikuro Obara

Kazuo Hokkirigawa

Katashi Tatsuno

Hiroshi Yoshikawa

Motoharu Akiyama

Tadashi Akahori

Akio Okamiya

Toshisada Koyama

Kaoru Matsumoto

Masayuki Yoneyama

Seiichi Matsuura

Yutaka Daikuhara

Kenji Fukunaga

Hirotaka Ichimura

Masamitsu Osada

Kyoji Kato

Naohiro Shiota

Kenichi Usuda

Hirotaka Yajima

A fluid dynamic bearing having a shaft () and a bearing sleeve () rotatably supported relative to each other. At least one of the shaft and the bearing sleeve is made of steel or stainless steel made of by weight C: 0.6&#x2dc;1.20%; Si: 1.0% or less; Mn: 1.0% or less; Cr: 10.5&#x2dc;18.0%; Mo: 1.0% or less; S.: 0.03% or less; and Fe. The dynamic pressure bearing surface () is formed by ridges () remaining in between multiple dynamic pressure grooves () formed by electrochemical machining.

Fluid dynamic pressure bearing for spindle motors and storage disk drive devices and having ridge portions between grooves in the fluid dynamic pressure bearing

A fluid dynamic pressure bearing device includes a shaft member () and a bearing member (), at least one of the shaft member or the bearing member being rotatable with respect to the other. A shaft member-side annular member () is fixed with respect to the shaft member. The shaft member-side annular member includes a large-diameter rim portion and a small-diameter outer circumferential surface portion. A bearing member-side annular member () is fixed with respect to the bearing member. The bearing member-side annular member includes an inner circumferential large-diameter step portion, and a small-diameter inner circumferential surface portion. A plurality of convex surface portions are formed either on a surface of the inner circumferential large-diameter step portion facing the large-diameter rim portion of the shaft member-side annular member, or on a surface of the large-diameter rim portion of the shaft member-side annular member facing a surface of the inner circumferential large-diameter step portion. A reflux groove () surrounds the convex surface portions.

Fluid dynamic pressure bearing device, spindle motor provided with the fluid dynamic pressure bearing device, and recording disk drive device

A fluid dynamic bearing mechanism for a motor () suitable for use in a hard disk drive and having a compact and thin shape, high bearing rigidity, and high rotating accuracy, and which securely keeps the rotor member () in place against shocks, and allows the inspection of lubricant supply amount easily. A fluid dynamic bearing mechanism having a capillary seal part () on one end of lubricant supply part formed by a minute gap including dynamic pressure grooves () formed on a shaft member () or a bearing member () is provided. An annular member () is fitted on the shaft member at the location corresponding to the capillary seal part, another annular member () is fitted on the bearing member at the location corresponding to the capillary seal part, a taper or step () is formed on the outer peripheral surface of the annular member on the shaft member side and the inner peripheral surface of the annular member on the bearing member side. These inner and outer peripheral surfaces are arranged to be close to and facing with each other so that the rotor member is prevented from disengaging from the bearing member, and the capillary seal part can be formed at the same time. An axial dynamic pressure bearing unit () is formed between the annular member on the shaft member side and one end of the bearing member.

Fluid dynamic bearing mechanism for a motor

A fluid dynamic bearing is provided. A structure in which a shaft member and an annular member fitted about the shaft member are rotatably supported by a bearing member and an annular member on the bearing member has a fifth gap for storing a lubricating fluid and supplying it to a second gap below the annular member on the shaft member and a third gap around its outer periphery through a fourth gap. The fourth and fifth gaps are tapered to produce a capillary drawing force toward the third and second gaps, so that the lubricating fluid may be supplied effectively from the fifth gap to the second and third gaps. This makes it possible to suppress any sudden formation of a reduced pressure upon exposure to impact or vibration to prevent the leakage of any lubricating fluid caused by the generation of bubbles, while making up for the loss of any lubricating fluid by vaporization.

Fluid dynamic bearing, motor and storage disk device

A hydrodynamic bearing having a bearing sleeve, a rotational shaft supported for rotation by the bearing sleeve, a bearing gap formed between the bearing sleeve and the rotational shaft, lubricating oil contained within the bearing gap, at least one hydrodynamic pressure-generating groove formed at an inner peripheral surface of the bearing sleeve; and an oil reservoir. The oil reservoir includes a gradually expanding section located in a position distanced from the pressure-generating groove and a first larger inner diameter, section located adjacently to the gradually expanding section. A second larger inner diameter section is located immediately below an opening of the bearing sleeve and an oil-repelling peripheral groove located between the first larger inner diameter section of the oil reservoir and the second larger inner diameter section. The oil-repelling peripheral groove and the second larger inner diameter section constitute an oil scatter and leakage prevention mechanism of the fluid dynamic bearing.

Fluid dynamic bearing and a storage disk drive with a spindle motor having the fluid dynamic bearing

The invention provides a special type bearing device that is insusceptible to damage, is light in weight, has a long service life and excellent wear resistance, is insusceptible to the effect of change in temperature, is easy to fabricate, and has little offensiveness towards mating members. Further, the same is capable of sufficiently retaining a lubricant such as oil and grease, and retaining the lubricant for a long period of time without the need of supplying oil during operation, thereby rendering it maintenance-free. That is, the special type bearing device as described above has an axial shaft, a pair of rotating bodies fixedly attached to the shaft, and a supporting body with which the rotating bodies are in contact, wherein any one of the shift, the rotating bodies, and the supporting body is made of RB ceramic or CRB ceramic.

Special type bearing device

A spindle motor is formed so as to support a pivot of a rotor by a pair of open bearings. The open bearings thus constructed will be less expensive and simple structures, so that a manufacturing cost thereof is reduced compared to a conventional spindle motor using a pair of ball bearings with shields. Accordingly, a low-cost spindle motor can be provided.

Spindle motor and method of manufacturing the same

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.

Motor

A synthetic resin composition includes at least one synthetic resin and RBC or CRBC particles dispersed in the resin. A method for preparing a synthetic resin composition includes mixing RBC or CRBC particles with a synthetic resin at a temperature near the melting temperature of the synthetic resin. Preferably, the method of includes the step of kneading the mixture.

Low-friction, high-dispersion synthetic resin composition containing fine particles of RB ceramic or CRB ceramic and a method for its preparation

A process for manufacturing miniature ball bearings that reduces material loss to improve manufacturing efficiency. The process consists of obtaining an inner and outer ring blank by cutting a first blank, forging the first blank to obtain a final blank, and separating the final blank to form an outer ring blank and an inner ring blank. The outer ring blank has an outer diameter of at most 13 mm. Cutting the first blank is performed by mechanically cutting and machining.

Process for manufacturing miniature ball bearings

A process for manufacturing miniature ball bearings that reduces material loss to improve manufacturing efficiency. The process consists of obtaining an inner and outer ring blank by cutting a first blank, forging the first blank to obtain a final blank, and separating the final blank to form an outer ring blank and an inner ring blank. The outer ring blank has an outer diameter of at most 13 mm. Cutting the first blank is performed by press cutting.

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.

Hydrodynamic pressure bearing system and spindle motor using the same

The object of the present invention is to provide a blower in which electrical components such as printed circuit board or electronic parts are isolated from the wind flowing through the blower to protect these components from moisture, dirt, dusts, or other harmful gas or substance contained in the wind, and to prevent the degradation of the insulating property such as the electric insulation or dielectric strength. A blower having an impelleradapted to be rotated by means of a motorcomprises a basefor supporting the motorthe base is provided and supported at the central portion of a framethrough staysa chamberfor accommodating electrical components formed in the base, the back portion of the chamber is adapted to be sealed by a removable coverwherein the chamber for accommodating electrical components is formed by the basehaving a flangeextending backward from the outer periphery thereof to form a cylindrical body with a bottom, the chamber has an opening at the rear thereof, and the rear opening of the base is occluded by the coverdetachably mounted by screws on the base

Axial electric fan blower with electric components housing sealed from moisture, dirt and dust or other harmful gas

The invention provides a weather-resistant exterior building material which has been unavailable in the past with respect to characteristics of keeping harmful insects such as white ants, and so forth away therefrom, light weight, a long service life, insusceptibility to variation in temperature, hygroscopicity, and easiness in fabrication, and an exterior article made up of the same. The weather-resistant exterior building material according to the invention makes use of a compact formed of RB ceramic, CRB ceramic, or fire-resistant CRB ceramic.

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Miyota-machi, Japan

Rikuro Obara