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Bearing Design Factors, Part 1 - Bearing Geometry and Technical Information || Dynaroll Ball Bearings




Part 1: Bearing Geometry

By Simon Harrison, Ph.D.

Miniature single-row deep-groove ball bearings are made to extremely high levels of precision and have an OD of 1/2 inch or less. Because of their small size, these bearings are generally used in applications where accurate, repeatable rotational performance and low torque are a necessity and load carrying capacity is a secondary issue. Miniature bearings are typically used in disk drives, positioning systems, medical equipment, guidance system components and other high-precision applications.

In order to optimize a design using miniature bearings, it is necessary to consider how the internal geometry of the bearings affects their performance in an assembly. This article addresses some fundamentals of bearing geometry and its implications on performance that an engineer might want to consider in selecting and using a particular miniature bearing.

Radial Play and Contact Angle

For a single-row deep-groove ball bearing, one of the major design parameters is radial play. This is defined as the maximum distance that one bearing ring can be displaced relative to the other ring in a direction perpendicular to the axis of rotation of the bearing.

Radial play can be thought of as the natural looseness of the bearing. The amount of looseness is controlled during manufacture and is specified by the user through selection of a given radial play for the bearing. Radial play is an important factor in the performance of a bearing since it affects the contact angle between the balls and the raceways.