Bearing Glossary

ABEC - The Annular Bearing Engineering Committee

ACBG - Airframe Control Bearings Group of the Society of Automotive Engineers

Age Hardening - Material hardening by aging

Aging - Change in the properties of a material that occurs at moderately elevated temperatures after hot working or heat treatment.

Air Bearing - Air cushion devices that are used to "float" heavy loads on a thin film of air

AISI - American Iron and Steel Institute, a standards organization.

Annealing - A type of heat treatment often used to soften a material. Annealing involves heating material to a specific temperature, holding it at that temperature for a known length of time, then cooling slowly to room temperature.

Annulus - In a rolling element bearing, the space between the inner and outer raceways

ANSI - American National Standards Institute, a standards organization

Armology - A hard plating applied to bearings for wear resistance

Austeniting - The breakdown of steel's ferrite and cementite structure.Partial austeniting occurs below the transformation temperature; full austeniting occurs above the transformation temperature.

Axial Movement - the amount a Bearing's inner race is able to move perpendicular to the outer race and perpendicular to the direction of rotation.

Ball Bearing - Any rolling bearing which uses balls as the friction reducing elements. There are three general types of ball bearings namely radial, thrust, and angular contact.

Ball Screw - A linear motion bearing where the inner race is helical. Ball screw assembly consists of a screw with a precision ground or rolled helical groove, a nut with an internal groove, and a circuit of precision steel.

Bearing - Device used to reduce friction, and constrain motion of mechanical devices along one or more axes. Bearings have three components i.e.an inner race, an outer race (and rolling elements.

Brinell Hardness Number - The measure of a material's resistance to indentation from a standard hard steel ball,

Brinelling - The indentation of inner or outer race material caused by the rolling elements. There are two types of brinelling, true brinelling and false brinelling.

Brinelling - True - The indentation of inner or outer race material caused by the rolling elements. True brinelling is a material deformation of a part and the movement of material due to excessive operating pressure, impact, dropping or hammering.

Brinelling - False - The indentation of inner or outer race material caused by the rolling elements. False brinelling is a wear issue where the indented material has been worn away

Cage - Also called Retainer, it is used to space, separate and retain the balls or rollers of a bearing. Cages may be of steel, plastic or brass.

Carburization / Carburizing - The tendency of a metal at high temperatures to absorb and diffuse carbon atoms throughout its structure. This enables the surface layer to be hardened

Cementation Coating - Any coating deposited on a metal surface by a high-temperature diffusion process.

Channeling Grease - A grease formulated so that rolling elements can create a permanent path through it

Chromizing - A high-temperature metal surface treatment.

Cold Working - Metalforming, normally at room temperature, under low strain and temperature conditions which induce strain hardening.

Conrad Bearing - Most common type of ball bearing, it is a nonseparable deep-groove ball bearing, with symmetrical inner and outer raceways. They can be used for radial loads, as well as thrust loads from either direction.

Corrosion - The chemical or electrochemical reaction between a material and its environment that causes deterioration of the material

Corrosion Embrittlement - The corrosive loss of a metal's ductility

Diamond Pyramid Hardness Number (DPHN) - A reference standard also known as Vickers Hardness.

Ductile Fracture - Material fracture failure characterized by "tearing" of the metal,

Dynamic Operating Capacity - A reference standard also known as Load Rating.

Elasticity - The degree to which stress-induced material deformation reverses

Elastic Limit - The maximum stress that a material can sustain before permanent deformation

Elastrohydrodynamic Lubrication - The movement of the lubricant between two moving surfaces.

Embrittlement - The process by which a material loses strength and/or ductility

Exfoliation - Corrosion that progresses laterally and parallel to the surface

Extra Light Bearings - Bearings that are narrower and/or have smaller outside diameters

Fatigue - The progressive quality of materials which leads to fracture under repeated or fluctuating stresses

Fatigue Strength - The maximum stress that a material can sustain for a specified (or standardized) number of stress cycles before it fails.

Filling Notch - Also known as a notch or loading groove it is designed such that it allows the balls to be loaded into the bearing but does not cut into the inner race.

Fretting - Uneven wear of the bearing races due to cycles of sliding or skidding

Full-Complement Bearing - A type of rolling element bearing that has the maximum possible number of rolling elements installed.

Gas Bearing - A particular journal bearing variation where pressurized gasses are used as lubricants.

Gonio Way - A type of linear motion bearing curved to describe the arc of a pendulum.

Graphitic Corrosion - A type of deterioration that occurs in gray cast iron products such as bearing housings.

Hardenability - The ability of a ferrous alloy to form martensite when quenched from a temperature above the upper critical temperature.

Heavywall Bearing - A particular class of journal bearing defined as having a wall thickness of at least 0.25" (6.5mm) and diameter of at least 6" (152mm).

Insert - The generic term for a bearing used in a mounted assembly

Internal Clearance - Also known as fit or radial clearance, it is the distance between the rolling elements and the bearing races.

ISO Standards Related to Bearings

ISO 15 - Rolling Bearings - Radial Bearings - Boundary dimensions, general plan

ISO 113 - Rolling Bearings - plummer block housings - boundary dimensions.

ISO 199 - Rolling Bearings - Thrust Bearings - tolerances

ISO 204 - Rolling Bearings - thrust bearings - boundary dimensions, general plan.

ISO 246 - Boundary dimensions - cylindrical roller bearings, separate thrust collars.

ISO 281 - Calculating the dynamic operating lifespan and load ratings for rolling element bearings

ISO 1002 - Rolling Bearings - Airframe Bearings - characteristics, boundary dimensions, tolerances, static load ratings.

ISO 1224 - Rolling Bearings - Instrument precision bearings

ISO 1132-1 - Rolling Bearings - Tolerances - Part 1: Terms and definitions.

ISO 1132-2 - Rolling Bearings - Tolerances - Part 2: Measuring and gauging principles and methods.

SO 1206 - IRolling Bearings - Needle Roller Bearings, dimension series 48, 49 and 69 - boundary dimensions and tolerances.

ISO 2795 - Dimensions and tolerances for plain bearings and sintered bushes.

ISO 10285 - Rolling bearings, linear motion, recirculating ball, sleeve type - metric series.

ISO 10317 - Rolling Bearings - metric tapered roller bearings - Designation System.

ISO 11687-1 - Plain Bearings - Pedestal Plain Bearings - Part 1: pillow blocks.

ISO 11687-2 - Plain Bearings - Pedestal Plain Bearings - Part 2: side flange bearings.

ISO 11687-3 - Plain Bearings - Pedestal Plain Bearings - Part 3: center flange bearings.

ISO 12043 - Rolling Bearings - Single Row Cylindrical Roller Bearings - chamfer dimensions for loose rib and non-rib sides.

ISO 12044 - Rolling Bearings - Single Row Angular Contact Ball Bearings - chamfer dimensions for outer ring non-thrust side.

ISO 12128 - Plain Bearings - Lubrication holes, grooves and pockets - Dimensions, types, designation and their application to bearing bushes.

ISO 12129-1 - Plain Bearings - Part 1: Fits

ISO 12129-2 - Plain Bearings - Part 2: Tolerances on form and position and surface roughness for shafts, flanges and thrust collars

ISO 12130-1 - Plain Bearings - Hydrodynamic plain tilting pad thrust bearings under steady-state conditions - Part 1: Calculation of tilting pad thrust bearings.

ISO 12130-2 - Plain Bearings - Hydrodynamic plain tilting pad thrust bearings under steady-state conditions - Part 2: Functions for calculation of tilting pad thrust bearings.

ISO 12130-3 - Plain Bearings - Hydrodynamic plain tilting pad thrust bearings under steady-state conditions - Part 3: Guide values for the calculation of tilting pad thrust bearings.

ISO 12131-1 - Plain Bearings - Hydrodynamic plain thrust pad bearings under steady-state conditions -- Part 1: Calculation of thrust pad bearings.

ISO 12131-2 - Plain Bearings - Hydrodynamic plain thrust pad bearings under steady-state conditions -- Part 2: Functions for the calculation of thrust pad bearings.

ISO 12131-3 - Plain Bearings - Hydrodynamic plain thrust pad bearings under steady-state conditions -- Part 3: Guide values for the calculation of thrust pad bearings.

ISO 12132 - Plain Bearings - Quality assurance of thin-walled half bearings - Design FMEA

ISO 12167-1 - Plain Bearings - Hydrostatic plain journal bearings with drainage grooves under steady-state conditions - Part 1: Calculation of oil-lubricated plain journal bearings with drainage grooves

ISO 12167-2 - Plain Bearings - Hydrostatic plain journal bearings with drainage grooves under steady-state conditions - Part 2: Characteristic values for the calculation of oil-lubricated plain journal bearings with drainage grooves

ISO 12168-1- Plain Bearings - Hydrostatic plain journal bearings without drainage grooves under steady-state conditions - Part 1: Calculation of oil-lubricated plain journal bearings without drainage grooves

ISO 12168-2 - Plain Bearings - Hydrostatic plain journal bearings without drainage grooves under steady-state conditions - Part 2: Characteristic values for the calculation of oil-lubricated plain journal bearings without drainage grooves

ISO 12240-1 - Spherical Plain Bearings - Part 1: Radial spherical plain bearings.

ISO 12240-2 - Spherical Plain Bearings - Part 2: Angular contact radial spherical plain bearings.

ISO 12240-3 - Spherical Plain Bearings - Part 3: Thrust spherical plain bearings.

ISO 12240-4 - Spherical Plain Bearings - Part 4: Spherical plain bearing rod ends.

ISO 12301 - Plain Bearings - Quality control techniques and inspection of geometrical and material quality characteristics

ISO 12302 - Plain Bearings - Quality characteristics - Statistical process control (SPC).

ISO 12303 - Plain Bearings - Quality characteristics - Calculation of machine and process capabilities

ISO 12306 - Plain Bearings - Measurement of wall thickness of thin-walled half-bearings and thin-walled bushes.

ISO 12307-1 - Plain Bearings - Wrapped Bushes - Part 1: Checking the outside diameter.

ISO 12307-2 - Plain Bearings - Checking of Wrapped Bushes - Part 2: Checking the inside diameter.

ISO 12308 - Plain Bearings - Quality assurance - Sample types - Definitions, applications and testing

ISO 13012 - Rolling bearings, linear motion recirculating ball, sleeve type - Accessories

ISO 13778 - Plain Bearings - Quality assurance of thin-walled half bearings - Selective assembly of bearings to achieve a narrow clearance range

ISO 15241 - Rolling Bearings - Symbols for quantities

Journal - A round section of shaft

Journal Bearing - Also known as a shell bearing, plain bearing, or hydrodynamic bearing.

Load Rating - A reference standard. Also known as Dynamic Operating Capacity.

Lubricant - A bearing lubricant lubricates the rolling and moving surfaces, protects from corrosion spreads heat evenly and inhibits contamination

Microtribology - The study of friction, wear and lubrication involved or required when two moving surfaces are in contact

Nanobearing - A bearing built on an atomic scale.

Needle Roller Bearing - A type of bearing that has long and thin rolling elements

Nitriding - Also known as Case Nitriding, it involves infusing nitrogen into the surface layer of the part at a specific temperature, changing the alloy at that layer.

Normalization - The process of heating a ferrous alloy material to more than the transformation temperature and slowly air-cooling.

Open - A bearing that operates with no seals or shields

Pear Skin - Industry jargon for the "fuzzy" appearance on the load-bearing surface of bearing races.

Pfund Hardness Number - A reference standard for the hardness of a coating on a material

Pickling - The removal of surface oxides

Powder Metallurgy - The use of metal powders under heat and pressure to produce shaped objects in a cavity like in clutch release bearing sleeves.

Refractory Metal - Generally, any metal with a melting point above the range for iron, cobalt and nickel.

Rockwell Scales - A series of reference standards for measuring material hardness.

Rolling Element Bearing - Any bearing where the relative motion of two surfaces is separated by balls or rollers as the friction-reducing component.

Rotor Dynamics - The study of rotating machines.

Rubbing Bearing - A type of bearing where the two surfaces come in contact or rub together.

SAE - Society of Automotive Engineers, a trade and standards organization.

Tempering - The process of heat treating hardened steel or cast iron, to decrease hardness and increase toughness.

Thrust Bearing - Bearing designed to operate with loading only on its axis.

Tribology - The study of friction, wear and lubrication involved or required when two moving surfaces are in contact.