Terms and Glossary
A.B.E.C. – Annular Bearing Engineering Committee
A.B.E.C. 1-3-5-7-9 – Grades of precision as determined by A.B.E.C.
Adapter Assembly – Metric/inch sleeve with locknut and lock washer
Adapter Sleeve – Axially slotted sleeve with cylindrical bore, tapered outside surface and male screw thread at small end used with locknut and lock washer for mounting of bearings with tapered bore on cylindrical outside surface of shaft.
Aircraft Bearing – Bearings that have been designed & approved for aircraft use.
Angular Contact Bearing – A type of bearing that has one ring shoulder partially or totally removed.
Anti-friction Bearing – Any bearing with a rolling element used to overcome friction
Axial Internal Clearance – The amount of possible movement parallel to the bearing axis of the inner ring in relation to the outer ring, also known as bearing end play.
Axial Load – Amount of load applied to the axis in a parallel manner, also known as thrust load.
Axis – An imaginary straight line about which an object rotates.
Ball – An individual spherical rolling element used in bearings.
Ball Bearing – A complete bearing unit assembled using balls as the rolling element.
Ball Cage – A device which is used in a ball bearing to retain, separate and guide the balls.
Ball Complement – The number of balls used in a complement ball bearing.
Ball Contact – The point of contact between raceways and the ball, usually measured in degrees.
Ball Diameter – The dimension of ball measured on the axis across the ball.
Ball Pocket – The receptacle in which the ball sits in its retainer
Basic Dynamic Load Rating – Basic dynamic load rating, Cr, is the calculated constant radial load (thrust load for thrust bearings) which a group of identical bearings with stationary outer rings can theoretically endure for rating life of 1 million revolutions of inner ring.
Bore — The inside diameter of a bearings inner ring.
Cam Follower – Anti-friction roller bearing for use in cam or track following applications.
Cartridge Bearing – An extra wide bearing that allows greater shaft support in addition to greater grease capacity.
Concentric – Having the same center. Most commonly a type of locking collar used on mounted bearings.
Cone – The inner ring of a roller assembly or taper bearing.
Conrad – A single deep groove ball bearing named after Joseph Conrad, the inventor of its assembly method.
Contact Angle – Nominal angle between the ball to race contact line and a plane through the ball centers, perpendicular to the bearing axis.
Counter bored Ball Bearing – Where the inner or outer race has one shoulder partially or completely removed. In most cases the outer ring is counter bored.
Double Row Bearing – A bearing with standard inner and outer dimensions that has two rows of rolling elements.
Double Row Maximum Capacity – A bearing that has a solid inner and outer with two raceways and filling notches to permit the maximum number of balls to be inserted.
Drawn Cup Needle Roller Bearing – Needle roller radial bearing with thin pressed steel outer ring (drawn cup), which may have one closed end or both ends open, usually employed without an inner ring.
Duplex Bearing – A bearing that has both faces flush ground for mounting in duplex arrangements.
Dynamic Load – The measurement of capacity denoted by the rotation of the inner ring while a stationary radial load is applied.
Eccentric – Not having the same center. Most commonly a type of locking collar used on mounted bearings.
End Play – The amount of possible movement parallel to the bearing axis of the inner ring in relation to the outer ring, also known as bearing end play.
Face – The side surface of a bearing.
Fillet Radius – The clearance needed to allow an inner race or outer race to seat next to a shoulder.
Filling Notch – A ball size groove in the inner ring of a bearing to allow the loading of balls into the bearing.
Finish – The smoothness of a materials surface as a result of machining.
Fit – The shaft of housing tolerances determined by operating characteristics.
Fixed Bearing – A bearing that is locked to the shaft or housing so that it can not float or move.
Floating Bearing – A bearing that was designed to allow movement axially between shaft and housing.
Full Complement Bearing – A bearing with out a cage or rolling element retainer.
Housing, Bearing – The opening in which a bearing is positioned or held to ensure proper positioning.
Housing Fit – The clearance necessary to hold a bearing in place based on use.
I.D. – The internal diameter or bore of an inner ring.
Inner Ring – The part of a rolling element bearing that is mounted on a shaft.
Inner Ring Raceway – The path the rolling element follows on the outside diameter of the inner ring.
Internal Clearance – The initial clearance before a bearing is mounted on a shaft or in a housing.
Internal Race – The pathway for the rolling element on the inner ring.
Lock Nut – A threaded nut which is slotted on the o.d and is used to hold bearings in place. Most commonly used with a lock washer.
Lock Washer – A stamped metal washer with tangs that will mate with the slots in the lock nut.
Loose Fit – A bearing with greater internal clearance than normal.
Maximum Capacity Bearing – A ball bearing that uses the maximum number of balls inserted in the bearing.
Misalignment – When a shaft or housing is not perpendicular to the axis.
Needle Roller – A long small diameter cylindrical steel roller.
O.D. – The outside diameter or outer diameter.
Outer Ring – The outer part of a bearing that fits into the housing and contains the inner race, cage and rolling elements.
Preload – A pre-determined axial load to increase rigidity in a bearing mounting.
Pre-lubricated Bearing – A shielded or sealed bearing that are pre-packed with greases or lubricants
Raceway – The path in which the rolling element follows.
Radial Clearance – The internal clearance or space that is built into the bearing based on operating conditions.
Radial Load – A downward load or perpendicular load on a bearing.
Radial Play – The amount of movement (play) when one ring is fixed and the other is moved up and down.
Radial Type Bearing – A bearing that’s primary use is for that of perpendicular loads.
Rating Life – The number of revolutions that 90% of a group of bearings will complete before the first evidence of fatigue develops.
Retainer – The ball separator or cage.
Seal – A positive contact rubber element that usually rides on the outer ring.
Self Aligning Ball Bearing – A ball bearing with two rows of rolling elements but a common raceway thus allowing the inner race and ball assembly to self align.
Separable – A bearing that may be separated completely or partially into its component parts.
Shaft Fit – Tolerances based of type, use and operating conditions of rolling element bearings.
Shield – A non contact metal plate used generally on ball bearings.
Shoulder – The side of a ball race, also a surface in a bearing application or shaft which axially positions a bearing and takes the thrust load.
Single Row – One row of rolling elements
Snap Ring – A removable ring used to locate and prevent a bearing from moving on a shaft or in a housing
Solid Cage – A solid ring type separator used in a radial or angular contact type bearings.
Spherical Roller Bearing – Self-aligning, radial rolling bearing with convex rollers or concave rollers as rolling elements. With convex rollers outer ring has spherical raceway, with concave rollers inner ring has spherical raceway.
Standard Bearing – A rolling element bearing design approved as standard by Anti-friction Bearing Manufacturers Association.
Static Load – The load acting on a non rotating bearing.
Thrust Load – Load exerted parallel to the axis of the shaft on which the bearing is mounted, also called thrust load.
Thrust Bearing – A rolling element bearing designed purely for axial load.
Thrust Face – The large shoulder or inner/outer ring on which the housing or shaft pushes.
Tolerance – The measurement of “leeway” in manufacturing bearings, shafts and housings.
Wide Inner Ring Bearing – A bearing with an extended inner race to give greater shaft support.