Hitachi, Ltd.

Hitachi Powdered Metals Co., Ltd.

Minebea Company, Limited

Other

The Kansai Electric Power Co., Inc.

Katsutoshi Nii

Kazuhiko Kawaike

Masaru Muranishi

Kenji Tomida

Yuuichi Yanagase

Hiroshi Nishida

Kazuhiko Kawakami

Noriyuki Kumasaka

Hideo Shikata

Hidekazu Tokushima

Satosi Uno

Sueo Akashi

Kouki Uefune

Shozo Saegusa

Takashi Kouno

Shinobu Yoshida

Motohiro Miyasaka

Jun Hirose

Hisanobu Kanamaru

Tsuyoshi Takahashi

Kinpei Okano

Toshikazu Takehana

Takashi Matsuki

Ichiro Hashimoto

Takeshi Nakajima

Hiroo Hiroyama

Michihiro Aizawa

Mitsuyuki Tsuyuki

Yoshiaki Yamauchi

Noriyuki Yoshimura

Kosho Ishizaki

Kooji Aizawa

Jun Matsubayashi

Motomichi Doi

Shunichi Togashi

Yasuhiro Yoshimura

Yoshishige Endo

Ikuo Nishida

Kyuichiro Nagai

Kunio Takada

Ryoji Okada

Hisahiro Miki

Masayuki Yamada

Tadashi Akahori

Kazuto Oyama

Akira Saruta

Kengo Hasegawa

Hisao Inoue

Takashi Kono

Shunzo Tomioka

Yoshihiro Sato

Osamu Sugimoto

Tomoki Hirata

Ichiro Hitomi

Tadayoshi Yano

Yoshihiro Satou

Teiji Horita

Ryoichi Nakashima

Nobuho Takagi

Muneo Maegawa

Minoru Kitsuya

Yoshiharu Yokota

Koozi Aizawa

Satoshi Uno

Tomoyuki Saitou

Nobukatu Sone

Fusanori Ohira

Makoto Kondoh

Seiichiro Terashima

A fluid dynamic pressure effect can be sufficient without receiving a large effect of viscous friction of lubricating oil with changes in the environmental temperature in which it is used, and smooth starting of the rotating shaft can be ensured by regulating the gap between the rotating shaft and bearing within a suitable range. An outer diameter of the bearing, D, a length in an axial direction of the bearing, L, a gap at a radial side which is between the rotating shaft and the bearing, C, and an inclining height of the bearing end surface to which the flange is faced, &#x3b4;, satisfy the expression L/D&#x3c;C/&#x3b4;. It is preferable that the inclining height, &#x3b4;, be 2 to 6 &#x3bc;m, the inner diameter of the bearing be 1 to 3 &#x3bc;m, and the gap at a radial side, C, be 1 to 4 &#x3bc;m.

Dynamic bearing unit

A production method for sintered bearing member comprises: compacting a metal powder into a green compact, sintering the green compact into a sintered compact; impregnating a resin solvent into the sintered compact, and removing the resin solvent adhering to a surface of the sintered compact, thereby exposing a matrix as sintered on a surface of the sintered compact. Pores existing in portions other than the surface are sealed with the resin.

Production method for sintered bearing member, fluid dynamic pressure bearing device, and spindle motor

The spindle motor includes a rotational shaftwhich has a conical portion, whose outer surface gradually widens toward a thrust dynamic pressure bearing, and a straight portionwith a fixed outer diameter. Radial dynamic pressure bearingsupports the radial load of the rotating shaft. The radial bearing has a conical bearing surfaceand a straight bearing surfacecorresponding to the conical portionand the straight portionof the rotating shaft, respectively. Rotating shaftis supported and aligned during rotation by fluid dynamic forces generated by the conical portion

Spindle motor

A sintered bearing is produced by a production method comprising: compacting a metallic raw material powder into a bearing green compact; sintering the green compact into a sintered compact; forming a resin coatingover the entire surface of the sintered compact; removing the resin coatingon a bearing surfaceof the sintered compact; and impregnating a lubricating fluid L through the bearing surfacefrom which the resin coatingis removed.

Sintered bearing and production method therefor

A bearing unit comprises a bearingformed of a sintered metal in which a magnetized magnetic powder is dispersed in its matrix and at least pores exposed on a bearing surface thereof are sealed by impregnation with a resin; a non-magnetic housingaccommodating the bearing; and a lubricating fluid M made of a magnetic fluid.

Bearing unit, production method therefor and spindle motor

A production method for a sintered bearing, comprises compacting a raw metallic material powder into a bearing green compact; sintering the green compact into a sintered compact; and forming a resin coating over the entire surface of the sintered compact by electrodeposition.

A spindle motor for magnetic disc device includes a hub having an inside and an outer peripheral side on which a magnetic disc is mounted, a rotary shaft having an axial direction and coupled with the hub so as to be integrally rotated therewith, with the motor being arranged on the inside of the hub. The hub, the rotary shaft and a part of the motor constitute a rotary body. A radial bearing having a length in the axial direction of the rotary shaft, for supporting the rotary body in a direction crossing the rotary shaft, and a thrust bearing for supporting the rotary body in the axial direction of the rotary shaft are provided. The thrust bearing has an outer diameter greater than the length of the radial bearing, and is arranged at a position which is inside of the motor and diametrically inward of the hub.

Spindle motor and magnetic disc device using thereof having radial and thrust bearings

A spindle motor comprises a housing including a through hole with a pair of apertures, one of the apertures being closed by a thrust plate and the other aperture being open; a bearing accommodated in the housing a rotating shaft inserted into the bearing a displacement restraining structure for restraining movement of the rotating shaft toward the open aperture by engaging the rotation shaft with the bearing a rotating member secured to the rotating shaft; and a motor generating electromagnetic function for rotating the rotating member. The through hole of the housing includes a large diameter portion A at the thrust plate side and a small diameter portion B at the open aperture side, and a stepped portion is formed at a transition portion between the large diameter portion A and the small diameter portion B. At least a portion of the bearing is located at the large diameter portion A side of the housing and engages with the stepped portion of the housing

A spindle motor used in a magnetic disc apparatus having a hub to which a magnetic disc is mounted and a rotary shaft to which the hub is fixed. The rotary shaft is located in a bearing casing having one end opened and the other end closed by a hydrodynamic pressure radial bearing, the rotary shaft being supported by a hydrodynamic pressure thrust bearing and the hydrodynamic pressure radial bearing. An inner diameter D and a width L of the hydrodynamic pressure radial bearing having a relationship of L/D<1.

Spindle motor and magnetic disc device with hydrodynamic bearings

A conventional plain bearing, in which dynamic pressure is generated by means of lubricating oil, has been assembled in such a way that the whole bearing device is assembled and then the lubricating oil is poured in the interior. As a result, residual air bubbles are produced to cause lowering of the dynamic pressure. The present invention uses magnetic fluid as lubricating oil, and adopts, for enclosing the fluid, a method in which at the time of assembling a spindle motor, a permanent magnet is used, magnetic fluid of a specified amount is previously held in a bearing unit by the magnetic attraction force, and after the insertion of a shaft, the magnetic fluid is supplied into a narrow space of a bearing part by a capillary attraction.

Assembly method of motor using magnetic lubrication fluid

A disk drive is realized, which omits running-in for stabilizing a change in a correcting function produced by sliding between balls and a rolling groove in an unbalance correcting mechanism, and prevents immobility and straying of balls, and which comprises a unit mechanism assembled by using 12 balls subjected to surface treatment with heptadecafluorodecyltrimethoxysilane and a turntable plated with a chemical nickel plating containing phosphorus and boron to have a thickness of 5 &mgr;m and by injecting 1 microliter of ester oil into the rolling groove, and further comprises a recess formed in a sidewall of the rolling groove of the unbalance correcting mechanism to prolong the service life of the correcting function.

Disk drive with unbalance correcting mechanism

A rotary shaft is rotatably supported by a hydrodynamic fluid radial bearing and a hydrodynamic fluid thrust bearing which are excellent in shock resistance, an bearing arrangement in which vibration in a translation mode of the shaft, among vibration components caused by unbalance force exerted to the rotary shaft, is supported by the radial bearing, and vibration in conical mode is supported by the thrust bearing, magnetic fluid is used as lubrication oil, and a permanent magnet is located between the radial bearing and the thrust bearing so as to apply a magnetic attracting force between the rotary shaft and the thrust bearing so as to carry out axial positioning in order to use the magnetic disc device in an arbitrary attaching posture. With this arrangement, the magnetic disc device using such a bearing arrangement can enhance portability, thinning and antishock ability, and reduce noise and power consumption, thereby it is possible to provide a note-type personal computer with a high degree of reliability.

Spindle motor and magnetic disc device with hydrodynamic bearing

A disk drive unit includes a rotary member, which has a spindle, and has an information-recording disk fixedly mounted thereon, and a bearing unit rotatably supporting the spindle. The bearing unit includes a radial bearing device, provided in opposed relation to an outer peripheral surface of the spindle, and a thrust bearing device provided in opposed relation to a distal end surface of the spindle. The radial bearing device has a concentric arc-shaped bearing surface, which is concentric with the circular outer periphery of the spindle, and a non-concentric arc-shaped bearing surface which is non-concentric with the circular outer periphery of the spindle. The disk drive unit further includes a motor for imparting a rotational force to the spindle, and a lubricating fluid filled in the bearing unit.

Disk drive unit with hydrodynamic fluid bearing unit and disk device with said drive unit

In a magnetic disk apparatus, the spindle motor is provided with a hole that penetrates the hub in the axial direction thereof. The hole permits fluid pressure on the outside and inside of the hub to become balanced, reducing the axial fluid force caused by the rotation of the spindle motor. The apparatus further includes a bearing provided with a groove for dynamic pressure generation and a magnetic lubrication fluid which, in combination with a permanent magnet, prevents oil leakage and scattering.

Magnetic disk apparatus, including spindle motor having air flow passage in hub for pressure balance

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Hitachi, Japan

Katsutoshi Nii