BEARING GLOSSARY
ABS (ANTILOCK BRAKE SYSTEM):
Ability to brake and steer at the same time. A braking system, usually electronically
controlled, that prevents wheel lock during heavy brake application.
ALL PURPOSE BEARING:
The Timken Company "AP" Bearing; a self-contained pre-assembled,
pre-adjusted, pre-lubricated, completely sealed unit. Applied to and removed
from an axle without exposing the bearing elements, seal or lubricant to
contamination or damage.
AXLE:
Rod or spindle on or with which a wheel revolves; the bar connecting two
opposite wheels. The shaft (axle) of an automobile fits through the bore
of a cone of the tapered roller bearing.
BALL BEARING:
An anti-friction bearing that uses a series of steel balls held between
inner and outer bearing races.
CAGED BEARING:
Similar to a full complement bearing, except that there are fewer rollers,
allowing room for the cage.
CLOSED-END BEARING:
A drawn cup bearing where one end of the cup has a solid face, which fully
encloses that end of the bearing. This allows the housing to be through
bored (straight housing). The closed end of the installed bearing seals
the housing.
FIXED BEARING:
Bearing which positions shaft against axial movement in both directions.
FLOATING BEARING:
Bearing so designed or mounted as to permit axial displacement between shaft
and housing.
GALLING:
A form of wear in which seizing or tearing of the gear or bearing surface
occurs.
HUB BEARING ASSEMBLY:
A packaged wheel-end unit that contains bearings, seals and all components
necessary for easy installation. It is pre-sealed, pre-lubricated and pre-set
for precise performance.
HUB GREASE CAP/DUST COVER:
A metal cap that fits over the outer end of the hub to keep grease in and
dirt out of the bearing assembly.
NEEDLE ROLLER:
Cylindrical roller with large length to diameter ratio. The length is between
three and ten times the diameter, which does not usually exceed 5 mm. The
ends of the needle roller may be one of several shapes.
OVERALL BEARING WIDTH:
The overall dimension when the cup and cone are mated, including rollers
and cage.
RACES:
The surfaces on the cup and cone where the rolling elements make contact.
ROLLERS:
Rolling elements that are located between the cone and cup.
RUNOUT:
Measurable irregularity across a plane surface, such as a disc brake rotor,
hub or wheel assembly.
SPINDLE:
A short tapered axle that supports a free rolling wheel. Also referred to
as a stub axle.
SPINDLE NUT:
A nut threaded on the end of the spindle for adjusting the wheel bearing
endplay or preload.
SPLINES:
External or internal slots or grooves cut in a shaft/gear/hub or yoke used
so that two different components must rotate together.
TAPERED ROLLER BEARING:
A friction reducing bearing that is made up of a cup, cone and tapered rollers,
which rotate around the raceway of the bearing.
TORQUE:
Something that produces torsion or rotation; the moment of a force causing
rotation.
TORQUE WRENCH:
A torque wrench measures the amount of turning force being applied to a
fastener (nut or bolt). Scales usually read in foot-pounds or Newton-meters.
TRUE ROLLING MOTION:
Tapered roller bearings naturally align themselves as a result of the balance
of forces on the bearing, keeping rolling elements moving smoothly in wheels
and other automotive applications.
UNIT BEARING:
A bearing that is sold as an assembled matched unit and is non-adjustable.
WEAR:
Damage resulting from the removal of surfaces material. Wear is generally
described as:
• Abrasive: Removal of materials from surfaces in relative motion by a cutting
or abrasive action of a hard particle, which is usually a contaminant.
• Adhesive: Removal of materials from surfaces in relative motion as a result
of surface contact. Galling and scuffing are the extreme cases.
• Corrosive: Removal of materials by chemical action.
Sources:
The Timken Company
Diald Industries, Inc
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