Spicer Drive Axles Application Guidelines - Manual (Page 102)

AXAG-0200 June 2009 102
Glossary
Roll-Off Containers
- Detachable open containers
generally used for hauling refuse, scrap, and construction
debris and are hoisted or winched over the rear of the truck
chassis for transport.
Rotor
- Braking surface for disc brake system. On heavy
trucks the rotor is generally cast iron and has vented
design. The rotor can be either separate or integral to the
hub. Rotors are also referred to a discs.
SAE (Society of Automotive Engineers)
- An
international organization of automotive/truck/bus
engineers who develop test procedures and requirements
for all ground transportation vehicles and their
components.
SAP
- Single anchor pin type brakes.
S-cam Brake
- Type of brake where mechanically-induced
rotation of an S-shaped cam forces brake linings against
the brake drum.
Scored drum
- Brake drum with a grooved friction
surface, resulting in excessive lining wear. Severe scoring
requires that a drum be machined, within manufacturer's
limits, before replacing the linings.
Secondary
- Roads that are typically well-maintained
gravel or crushed rock, surface conditions are not as
favorable as on primary roads.
Semi-active Suspension
- A suspension that changes its
ride quality in response to hitting a bump or alteration in
the road. This change must occur in milliseconds to be
effective.
Semi-trailer
- Trailer used in connection with truck tractor .
Sensor Sleeve
- Rigid steel sleeve mounted in the knuckle
to provide a pilot for the ABS sensor to be mounted in
close proximity to the tone ring on the hub.
Service Brake Priority
- A type of trailer brake control
valve that prioritizes delivery of air to a trailer's service
reservoirs, to provide braking ability, after being hooked to
a tractor . Releasing a trailer's parking brakes is a secondary
concern.
Service Brake
- As opposed to spring or parking brakes,
that portion of the brake system used for normal brake
application while driving.
Shift Inhibitor
- Pneumatic-mechanical system that delays
the shifting process until the engine has returned to idle
speed. This prevents drivetrain damage due to high RPM
shifting.
Shims
- Spacers used to fill in the space between knuckle
and top of beam after thrust washer is installed on the
bottom side of the beam.
Single-reduction Axle
- Any axle assembly with only one
gear reduction through its differential ring gear and drive
pinion.
Site Travel
- Slow speed operation up to 5mph at a job site
not to exceed 5% of total operating miles of the vehicle.
Slack Adjuster
- Also called a brake adjuster, this is a
lever connecting the brake chamber push rod with the
foundation brake camshaft. It provides torque to rotate the
brake camshaft when the brake treadle is depressed. It also
provides a means of adjusting clearance between brake
shoes and the drum to compensate for lining wear. Some
models are automatic while others require manual
adjustment. See " ABA ".
Slip Torque
- Engine torque required to slip wheels on the
driving surface.
SLR (Static Loaded Radius)
- The distance between the
dual tire centerlines or the distance between the tire
centerlines on a single tire.
SMC (Suspension Mounting Centers)
- The distance
from the centerline of axle to the ground, under rated tire
capacity, with the tire at rest.
Soft Dampened Clutch
- Special type of clutch that
features a torsional mechanism that avoids impact loads
being transmitted through the driveline.
Speed Sensor, ABS
- An electromagnetic device that, in
conjunction with a rotating toothed wheel, generates an
electrical signal proportional to the wheel speed and
transmits the information to the ABS Electronic Control
Unit (ECU).
Spider
- Spider-like casting or forging containing axle
differential or the foundation brake structural member.
Spindle
- A shaft-like projection from the steering knuckle
or the drive axle housing to which the wheel is mounted.
Spinout
- When the maximum drive slip resistance has
been exceeded by its tractive effort and a sudden increase
in drive wheel speed occurs.
Spiral Bevel Gear
- The teeth of both the ring and the
pinion are tapered and are cut on a spiral so that they are at
an angle to the centerline of the pinion shaft.
Spitter Valve
- Slang for automatic drain valve.