Nsk Corporation

Hiromitsu Muraki

Katsuhiko Tanaka

Ikunori Sakatani

Shigeru Endo

Chuichi Sato

Toru Takamizawa

Shoji Noguchi

Hiromitsu Asai

Takashi Seshimo

Hiroshi Tani

Norihiro Aoki

Kenji Takei

Kazuhiro Uemura

Takafumi Yasuhara

Hideo Okano

Etsuo Maeda

Shoji Moguchi

Norikazu Kitagawa

A pair of pre-loaded ball bearingsare fixed to a shafthaving a flangeto be a reference surface Q formed on one end, and where a clearance C is secured between the surfaceon the flange side of the inner raceof the bearingon the side of the flangeand the flange surface

Rolling bearing apparatus for swing arm

Two bearings are used to rotatably support the pivot with reference to a fixed shaft. The swing arm is highly precisely fixed to the pivot . The outer diameter of the outer race of the lower bearing is larger than the outer diameter of the outer race of the upper bearing . The end surface of the outer race of the outer race of the lower bearing and the outer periphery of the outer race of the upper ball bearing are used as a reference surface to fix the swing arm . The housing used in the prior art is eliminated from the structure according to the present invention to reduce the number of parts.

Rolling bearing unit

A rolling-bearing unit comprising a pair of bearing assembled such that the tolerance range of the radial clearance or contact angle of the ball bearings is divided into a plurality of divisions, and that a pair of ball bearings is selected from the same division, and that a pre-load, which is set according to the division, is applied to the selected pair of ball bearings as they are installed in the unit.

The locus of the displacement of the centers of the balls of a ball bearing is made elliptical and the radial bearing rigidity of the ball bearing in one radial direction is made greater than the radial bearing rigidity in another radial direction orthogonal to the one radial direction, or at least one of the axial length of the portion on the outer diametral surface of the inner race of the ball bearing which is fitted to a shaft and the axial length of the portion on the outer diametral surface of the outer race of the ball bearing which is fitted to a housing is made &frac12; or less of the bearing width of the ball bearing, whereby the radial rigidity of a ball bearing device is made very small as compared with the radial rigidity in the prior art. As a result, the stability of a swing arm system can be enhanced and higher speed and higher accuracy of control become possible.

Method of stabilizing high-speed control of ball bearing device

The locus of the displacement of the centers of the balls of a ball bearing is made elliptical and the radial bearing rigidity of the ball bearing in one radial direction is made greater than the radial bearing rigidity in another radial direction orthogonal to the one radial direction, or at least one of the axial length of the portion on the inner diametral surface of the inner race of the ball bearing which is fitted to a shaft and the axial length of the portion on the outer diametral surface of the outer race of the ball bearing which is fitted to a housing is made &frac12; or less of the bearing width of the ball bearing, whereby the radial rigidity of a ball bearing device is made very small as compared with the radial rigidity in the prior art. As a result, the stability of a swing arm system can be enhanced and the higher speed and higher accuracy of control become possible.

Ball bearing device for a swing arm

A rolling bearing according to the present invention comprises an inner race , an outer race and a plurality of balls disposed therebetween. The inner race has a raceway surface on its outer peripheral surface. The outer race includes a raceway surface on its inner peripheral surface. The balls are rotatably interposed between the raceway surfaces of the inner and outer races. A lubricant is enclosed in a space formed between the raceways of the outer and inner races by an amount of 0.3% to 3% of the capacity of the space.

Rolling bearing

A rolling bearing according to the present invention comprises an inner race,, an outer race,and a plurality of balls,disposed therebetween. The inner race,has a raceway surface on its outer peripheral surface. The outer race,includes a raceway surface on its inner peripheral surface. The balls,are rotatably interposed between the raceway surfaces of the inner and outer races. A lubricant is enclosed in a space,formed between the raceways of the outer and inner races by an amount of 0.3% to 3% of the capacity of the space.

A disc drive device includes a rotational assembly which is adapted to mount a disc thereon and is rotatably driven by a motor. The rotational assembly is rotatably supported on a support assembly by a radial hydrodynamic fluid bearing and a thrust bearing. An axial load is applied to the thrust bearing by a magnetic attractive force of up to 30N and is greater than a dead weight of the rotational assembly.

Rotational assembly for disc drive device having small runout and reduced axial displacement

In a spindle motor for a disc drive in which a rotatable body having a disc mounted thereon is rotatively driven by a motor, the rotatable body is rotatably supported on a support member through a ball bearing and a hydrodynamic fluid bearing, and a preload equal to or greater than an axial load of 1N is imparted to the ball bearing.

Spindel motor for a disc drive

A novel hydro-dynamic fluid bearing device is herein disclosed which comprises a cylindrical shaft, a substantially cylindrical bearing member for axially supporting the shaft rotatably in a cylindrical hole having a bottom surface, a supporting member fixed on one side of the shaft and the bearing member, and a rotation member fixed on the other side of the shaft and the bearing member and rotatably supported on the supporting member, grooves for generating hydro-dynamic fluid being formed on at least one of the outer peripheral surface of the shaft and the inner peripheral surface of the cylindrical hole of the bearing member, wherein the bearing member is made of a resin material, and the outer peripheral surface of the substantially cylindrical portion is fixed to an annular reinforcing member having a higher rigidity than the bearing member.

Hydro-dynamic fluid bearing device and manufacturing method of the same

The locus of the displacement of the centers of the balls of a ball bearing is made elliptical and the radial bearing rigidity of the ball bearing in one radial direction is made greater than the radial bearing rigidity in another radial direction orthogonal to the one radial direction, or at least one of the axial length of the portion on the inner diametral surface of the inner race of the ball bearing which is fitted to a shaft and the axial length of the portion on the outer diametral surface of the outer race of the ball bearing which is fitted to a housing is made 1/2 or less of the bearing width of the ball bearing, whereby the radial rigidity of a ball bearing device is made very small as compared with the radial rigidity in the prior art. As a result, the stability of a swing arm system can be enhanced and higher speed and higher accuracy of control become possible.

A bearing device includes a housing, a shaft arranged in an inner circumference of the housing, and a pair of bearings arranged between the shaft and the housing, and spaced from each other in an axial direction of the shaft, at least one of the bearings comprising a sleeve inserted in the housing and formed cylindrically. The sleeve has an outer layer portion including an outer cylindrical surface and an inner layer portion including an inner cylindrical surface, the outer layer portion being harder than the inner layer portion, the inner cylindrical surface having a groove for generating dynamic pressure. The sleeve is improved in working accuracy, and the dynamic pressure generating grooves can be formed with ease.

Growing community of inventors

Fujisawa, Japan

Hiromitsu Muraki