Ntn Corporation

Kazuo Okamura

Natsuhiko Mori

Isao Komori

Yasuhiro Yamamoto

Makoto Shiranami

Tsugito Nakazeki

Fuminori Satoji

Yoshinobu Akamatsu

Fuyuki Ito

Ryouichi Nakajima

Masafumi Okuma

Kenichi Mitani

Kenji Hibi

Masakazu Hirata

A maximum diameter (d) of each of surface openings formed in a bearing surface through melting of Sn metal powder as a binder is set within a range of 0 &#x3bc;m&#x3c;d&#x2266;25 &#x3bc;m. In order to attain the range, binder metal powder having a maximum particle diameter of 25 &#x3bc;m or less is used.

Sintered bearing

A sintered metal bearing is obtained by compression-molding of a raw-material powder containing at least a Cu powder, an SUS powder, and a pure Fe powder and thereafter sintering a compression-molded body at a predetermined temperature.

Sintered metallic bearing and fluid dynamic bearing device equipped with the bearing

Assembly precision in a motor is improved and greater cost reduction is achieved. A fluid dynamic bearing apparatuscomprising a housingand bearing sleeveas fixed-side members, a shaft memberas a rotational-side memberhaving a portionfor mounting a rotor magnet, and a disk hub, the shaft memberbeing supported by the bearing sleevein the radial direction in a non-contact manner by the hydrodynamic effect of a lubricating oil produced in a radial bearing gap between the inner circumferential surfaceof the bearing sleeveand the outer circumferential surfaceof the shaft member while the shaft memberis in rotation, the apparatuscomprising a disk hubwhich is fixed on the shaft memberand has a portionfor mounting the rotor magnet, and the disk hubbeing a molded resin article formed by insert-molding using the shaft memberas an insert piece.

Fluid dynamic bearing apparatus and a motor using the same

Assembly precision in a motor is improved and greater cost reduction is achieved. A fluid dynamic bearing apparatus includes a housing and bearing sleeve as fixed-side members, a shaft member as a rotational-side member having a portion for mounting a rotor magnet, and a disk hub. The shaft member is supported by the bearing sleeve in the radial direction in a non-contact manner by the hydrodynamic effect of a lubricating oil produced in a radial bearing gap between the inner circumferential surface of the bearing sleeve and the outer circumferential surfaceof the shaft member while the shaft member is in rotation. The apparatus includes a disk hub which is fixed on the shaft member and has a portion for mounting the rotor magnet, and the disk hub is a molded resin article formed by insert-molding using the shaft member as an insert piece.

The porous oil-impregnated bearingcomprises a bearing bodymade of a porous material, and oil retained in the pores of the bearing bodyby impregnation with lubricating oil or lubricating grease. The inner peripheral surface of the bearing bodyis formed with a bearing surfaceopposed to an outer peripheral surface of a shaft to be supported, with a bearing clearance defined therebetween. The bearing surfacehas a first region min which a plurality of hydrodynamic pressure generating groovesinclined in one direction with respect to the axial direction are circumferentially disposed, a second region mwhich is axially spaced from said first region mand in which a plurality of hydrodynamic pressure generating groovesinclined in the other direction with respect to the axial direction are circumferentially disposed, and an annular smooth region n disposed between the first and second regions mand m

Hydrodynamic type porous oil-impregnated bearing

The squareness of the both end surfaces of the flange portion with respect to the outer circumference of the shaft portion of the shaft member is set to 0.001 mm or less respectively, and the flatness of both end surfaces of the flange portion is set to 0.001 mm or less respectively. The squareness of the end surface of the bearing member with respect to the inner circumference of the bearing member is set to 0.002 mm or less, and the flatness thereof is set to 0.0015 mm or less. The flatness of the inner surface of the bottom portion of the housing is set to 0.002 mm or less.

Hydrodynamic bearing unit

Method of producing a sintered oil retaining bearing

The porous oil-impregnated bearing comprises a bearing body made of a porous material, and oil retained in the pores of the bearing body by impregnation with lubricating oil or lubricating grease. The inner peripheral surface of the bearing body is formed with a bearing surface opposed to an outer peripheral surface of a shaft to be supported, with a bearing clearance defined therebetween. The bearing surface has a first region m in which a plurality of hydrodynamic pressure generating grooves inclined in one direction with respect to the axial direction are circumferentially disposed, a second region m which is axially spaced from said first region m and in which a plurality of hydrodynamic pressure generating grooves inclined in the other direction with respect to the axial direction are circumferentially disposed, and an annular smooth region n disposed between the first and second regions m and m

A hydrodynamic type bearing unit comprises a shaft member , a bearing member and a bearing clearance formed between the shaft member and a bearing member to produce a hydrodynamic pressure during the rotation of a shaft member . The bearing clearance is composed of a first clearance C on one axial side and a second clearance C on the other axial side and the first and second clearances C and C are mutually oppositely inclined against an axial direction.

Hydrodynamic type bearing unit

A hydrodynamic type bearing unit with enhanced moment load capacity. In the bearing unit, a radial bearing clearance and thrust bearing clearances are set at such widths that a tilted spindle member comes into contact at the outer periphery of its spindle with both axial ends of a radial bearing surface opposed thereto, as well as at the rims of both end faces of its flange portion with respective thrust bearing surfaces opposed thereto, so that the moment load can by supported by both the radial bearing part and the thrust bearing part. Specifically, the radial bearing clearance &dgr; and the thrust bearing clearances &dgr; are set in accordance with the expression D&dgr; /L&plus;&egr;&gE;&dgr; &gE;D&dgr; /L (where D is the diameter of the flange portion, L is the axial length of the radial bearing part, and &egr; is a machining error).

A dynamic pressure bearing-unit is provided, which includes a shaft member ( ) with a shaft ( ) and a flange portion ( ), a radial bearing ( ) for supporting the shaft member ( ) in the radial direction, and a thrust bearing ( ) for supporting the flange portion ( ) of the shaft member ( ) in the direction of thrust. The radial bearing ( ) and the thrust bearing ( ) support the shaft member ( ) by dynamic pressure action out of contact, respectively, and the shaft ( ) and the flange portion ( ) are constructed in one piece. In this case, dynamic pressure grooves of the thrust bearing ( ) are provided on the end surface of the bearing member ( ) or on the upper surface of the thrust support portion ( ) opposite to the flange portion ( ).

Dynamic pressure bearing-unit

Sintered oil retaining bearing and spindle motor for information equipment

The porous oil-impregnated bearing,comprises a bearing body,made of a porous material, and oil retained in the pores of the bearing body,by impregnation with lubricating oil or lubricating grease. The inner peripheral surface of the bearing body,is formed with a bearing surface,opposed to an outer peripheral surface of a shaft to be supported, with a bearing clearance defined therebetween. The bearing surface,has a first region m,in which a plurality of hydrodynamic pressure generating grooves,inclined in one direction with respect to the axial direction are circumferentially disposed, a second region m,which is axially spaced from said first region m,and in which a plurality of hydrodynamic pressure generating grooves,inclined in the other direction with respect to the axial direction are circumferentially disposed, and an annular smooth region n disposed between the first and second regions m,and m

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Kuwana, Japan

Kazuo Okamura