Koyo Seiko Company, Ltd.

Shinji Abe

Kiyoshi Tanimoto

Kazuya Suzuki

Masahiro Mukasa

Hirokazu Takii

Hirotsugu Kusano

Tetsuo Oda

Atsushi Yao

Tomohiro Haruta

Masayuki Funatsu

Within bounds on both sides of an axial center of each of the raceways of an outer and inner ring, a curvature radius of a raceway portion in a dimensional range covering at least 45% of a raceway width with respect to the axial center thereof is defined to be within the range of between &plusmn;1 &mgr;m to/from a mean curvature radius of the raceway in the dimensional range.

Rolling bearing

A ball bearing has an outer race, an inner race, and a retainer disposed between the outer race and the inner race. The retainer comprises an annular member having a first annular surface and a second annular surface disposed opposite the first annular surface, a plurality of annularly spaced pockets formed in the first annular surface of the annular member, and a plurality of annular spaced fingers each having inner and outer surfaces and projecting generally axially from the first annular surface of the annular member so that the pockets are disposed between adjacent inner surfaces of respective ones of the pairs of fingers, the first annular surface of the annular member having external and internal edges and a plurality of surface portions each disposed between adjacent outer surfaces of respective ones of the pairs of fingers and inclined toward the second annular surface of the annular member from the external edge to the internal edge. Balls are disposed in respective ones of the pockets of the annular member and coact with the outer and inner races.

Ball bearing

A rolling bearing composed of a combination of bearing wings formed with a steel material and rolling elements formed with a ceramic material, wherein the residual austenite amount of the steel material forming the rolling rings is controlled to a specific value. By the construction, at rolling of the rolling elements formed with a relatively hard ceramic material, the occurrence of the surface scratches of the rolling elements can be restrained, which results in restraining the vibrations and noises caused by the rolling bearing.

A rolling bearing composed of a combination of bearing wings formed with a steel material and rolling elements formed with a ceramic material, wherein the residual austenite amount of the steel material forming the rolling rings is controlled to a specific value. By the construction, at rolling of the rolling elements formed with a relatively hard ceramic material, the occurrence of the surface scratches of the rolling elements can be restrained, which results in restraining the vibrations and noises caused from the rolling bearing.

A rolling bearing comprises an inner ring, an outer ring and a plurality of rolling elements therebetween, and is used, for example, in a spindle motor for driving a hard disk. The inner ring is made of, for example, high-carbon chromium steel, the outer ring is made of, for example, stainless steel, and each rolling element is made of ceramics, for example zirconia, of which coefficient of linear expansion is in the range of 7&times;10,/&deg; C. to 15&times;10,/&deg; C. The bearing rings and the rolling elements are substantially equal to each other in coefficient of linear expansion. Thus, the change in pre-load due to temperature variations is small.

Rolling bearing and rolling bearing device

A ball bearing assembly is provided with a ball retainer having a radially extending guide portion that serves to guide the ball retainer relative to either an inner or an outer ring of the ball bearing assembly. The ball retainer is provided with a series of ball pockets with each of the ball pockets having a central cylindrical portion that transitions smoothly into inner and outer portions having spherical configurations. The diameter of the central cylindrical portion is smaller than the diameters of the inner and outer spherical portions. The configurations of the ball pockets ensures that a clearance will be maintained between each of the balls and the edge portions of the ball pockets even when the ball retainer is deflected relative to the inner and outer rings of the ball bearing assembly. The internal configuration of the ball pockets ensures that the amount of lubricant retained within the ball pockets is optimized. The optimization of the amount of lubricant retained within the ball pockets results in a desired level of frictional torque generated by the ball bearing assembly and the elimination of abnormal noises generated during high speed rotation of the ball bearing assembly.

Bearing assembly

A ferrofluid seal apparatus comprises magnetic fluid holding means for storing a magnetic fluid with one of an inner and an outer elements which are relatively rotated. The magnetic fluid holding means has a storage section for storing a part of the magnetic fluid which flows out of said magnetic fluid holding means.

Ferrofluid seal apparatus

A ferrofluid seal apparatus comprises magnetic fluid holding or positing means for storing or retaining a magnetic fluid in a sealing arrangement wherein inner and outer elements are relatively rotated. The magnetic fluid holding means includes an arrangement for retaining the magnetic fluid which flows out from its original position.

A method for fabricating a spindle housing with a ball bearing has the following steps: positioning the ball bearing in a cavity of a molding tool in a condition that a pre-load is provided to eliminate an internal clearance of the ball bearing, and injecting synthetic resin within the cavity of the molding tool after relative movement of the outer race and inner races of the ball bearing due to the pre-load.

Growing community of inventors

Nara, Japan

Shinji Abe