Angular contact bearings are designed such that a contact
angle between the races and the balls is formed when the bearing is in use. The
major design characteristic of this type of bearing is that one, or both of the
ring races have one shoulder relieved, or higher than the other. In order for
these bearings to function properly, they must be assembled with a thrust load.
This loading (or preload) creates a line of contact (or contact angle) between
the inner race, the ball and the outer race. The preload can be built into the
bearing or created when the bearing is inserted into an assembly. The contact
angle varies from 15° to 40° and is measured relative to a line running
perpendicular to the bearing axis. Angular contact bearings are unidirectional
thrust bearings that can withstand heavy thrust loads and moderate radial loads.
Important dimensions to consider when searching for angular contact bearings include design units, bore, outside diameters, and outer ring width. Design units can be in either inches or metric units. Some manufacturers may specify parts in both. The bearing industry uses a standard number system for bearings with metric diameter bores. For bore sizes 04 and up multiply by 5 to obtain the bore in millimeters. If the bore is a hex enter the dimension across the flats. If the bore is tapered enter the smaller diameter. The outside diameter of the bearing includes the housing if a housed unit, but excludes the flange if a flanged bearing.
Important operating specifications to consider when searching for angular contact bearings include rated speed, static radial load, and dynamic radial load. The rated speed for a bearing running with grease lubrication is lower than a bearing with oil lubrication. The static radial load is the maximum radial load bearing can endure without excessive permanent deformation. The dynamic radial load is the calculated constant radial load, which a group of identical bearings with stationary outer rings can theoretically endure for a rating life of 1 million revolutions of the inner ring.
Manufacturers typically assign an ABEC rating to bearings. ABEC (Annular Bearing Engineers' Committee) ratings classify different accuracy and tolerance ranges for bearings. The higher the ABEC number the tighter the bearing tolerances. Please consult tables in the search form for Angular Contact Bearings for tolerances and other rating equivalents.
Angular contact bearings can have a number of different styles of seals or shielding. Seals and shields provide protection from contamination and as a retainer for lubricant. Seals provide better protection and lubricant containment than shields, but have lower maximum speed capabilities. Types include single seal, double seal, single shield, and double shield. Angular contact bearings may be constructed of special materials including stainless steel, plastic, and ceramic hybrid. They may also be plated; common plating materials are cadmium and chrome.
Koyo Thrust Bearings