Nsk Corporation

Tetsuo Unno

Yoshio Shoda

Tatsunobu Momono

The roller bearing comprises a plurality of rollers which are respectively interposed between a concave-shaped race surface formed on an outer race and a concave-shaped race surfaces formed on an inner race . Each of the rollers is structured such that the central portion of the rolling surface thereof is formed by a first convex-shaped bus which corresponds to the concave-shaped race surfaces and , while the two end portions of the rolling surface thereof are respectively formed by second buses which have a radius of curvature smaller than the radius of curvature of the first bus

Roller bearing

In the roller bearing, plural of rollers are interposed between an outer raceway of an outer race and an inner raceway of an inner race and a collar portion is formed along one of the axial-direction end portions of the inner raceway The central portion of one of the outer race and inner raceways and the opposing outer peripheral surface of the roller is formed of a first bus with a given radius of curvature. The two end portion sides adjacent to the central portion are formed of a second bus with such a radius of curvature that causes the two end portion sides to part away from the other. The collar surface of the collar portion contacting with an end face of the roller being a convex-shaped spherical surface is formed as a concave-shaped spherical surface.

The roller bearing,comprises a plurality of substantially cylindrical-shaped rollers,which are respectively interposed between a concave shaped race surface,formed on an outer race,and a concave-shaped race surfaces,formed on an inner race,Each of the rollers,is structured such that the central portion of the rolling surface thereof is formed by a first convex-shaped bus,which corresponds to the concave-shaped race surfaces,and,while the two end portions of the rolling surface thereof are respectively formed by second buses,which have a radius of curvature smaller than the radius of curvature of the first bus

A sphere is supported in a floating condition by a pneumatic bearing so as to be rotated by compressed air sprayed from a nozzle. The sphere has a single point magnetized on its surface, and is placed on its rotating axis. If the sphere has a dynamic imbalance, the single point is subjected to pressesion around its inertia axis, the locus and displacement velocity of which are measured by the Hall elements arranged in an arc line around the pneumatic bearing, thereby obtaining the dynamic imbalance of the share.

Method and apparatus for measuring dynamic imbalance of sphere

1. A ball bearing comprising; a first race ring having a surface formed with a first race surface thereon, a second race ring having a surface formed with a second race surface thereon, and a plurality of balls provided so as to be freely rotatable between the first race surface and the second race surface, the ball bearing being used under conditions wherein a product d.sub.m .multidot.N of a pitch circle diameter d.sub.m mm of the plurality of balls, and a rotational speed N rpm of the second race ring relative to the first race ring is greater than 1,000,000 mm.multidot.rpm, characterized in that for each of the plurality of balls, a ratio .DELTA.I/I of a dynamic imbalance amount to a moment of inertia I, is less than (3.1.times.10.sup.7 /(d.sub.m .multidot.N).sup.2)+2.7.times.10.sup.-5.

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Kanagawa, Japan

Tetsuo Unno