Steering Systems

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Steering Systems
Driver Input
When the steering wheel
is rotated from lock-to-lock
the the front wheels turn
about 30 degrees in each
direction or 60 degrees
total
A steering ratio of 15:1 is
common for passenger
cars
fifteen degrees of
steering wheel rotation
moves the front tires one
degree
Variable ratio
Steering and Suspension
Steering Wheel and Column
The steering wheel,
column, u-joints and
flex couplings deliver
the driver s input to the
steering gear, provide
vehicle feedback to the
driver and insulate the
driver from excessive
road feel or harshness
The steering column is
also deigned to collapse
during a collision
Steering and Suspension
Parallelogram Steering
The parallelogram
linkage insulates the
driver from road noise
and vibration, but
component wear leads
to a feeling of steering
looseness
Pitman arm
Center link
Idler arm
Tie rods
Tie rod ends
Steering and Suspension
Idler Arm
The idler arm is bolted
to the frame and
supports the center link
opposite the pitman arm
Excessive idler arm
play may cause
steering wheel play and
allow the vehicle s toe
setting to change while
driving or under load
Steering and Suspension
Tie Rod Ends
Tie rods ends connect the tie
rod to the center page link and the
steering knuckle
Tie rod ends are often
checked for proper
articulation effort
Excessive tie rod end play
may cause steering wheel
play and allow the vehicle s
toe setting to change while
driving or under load
Binding tie rod ends can
cause increased steering
effort or binding
AUMT 1316 - Steering Systems 10/15/2004
2
Steering and Suspension
Recirculating Ball Gearbox
Converts the
steering wheel s
rotary motion into
linear motion
Commonly used on
light trucks and
large cars
Minimal internal
friction
Road shock isolation
Steering and Suspension
Steering Gearbox Components
Stub Shaft
Sector Gear
Sector Shaft
Worm Shaft
Housing
Steering and Suspension
Ball-Nut Operation
A series of ball bearings is
placed between the worm
gear and the ball nut
The ball bearings cannot
move up or down and the
balls bearings follow the
track in the worm gear
The ball nut follows the
ball bearings as the
steering wheel turns
The ball nut meshes with
the sector gear
Steering and Suspension
Steering Gear to Linkage
Steering wheel drives the
steering shaft
Steering shaft drives the
worm shaft
Worm shaft drives the
balls
Balls drive the ball nut
Ball nut drives the sector
gear
Sector gear drives the
sector shaft
Sector shaft drives the
pitman arm
Pitman arm drives the
center link
Center page link drives the
inner tie rod end
Inner tie rod end drives
the tie rod
Tie rod drives the outer tie
rod end
Outer tie rod end drives
the steering knuckle
Steering and Suspension
Adjustment
Two adjustments are
commonly required for
recirculating ball
steering gear service:
Worm-shaft preload for
manual steering gears
Sector-shaft mesh-load
Sector shaft mesh-load
procedures are
commonly available for
bench and on-car
service
Steering and Suspension
Rack and Pinion Steering
Light and compact
design
Pinion drives rack
Rack drives tie rods
Tie rods drive steering
knuckle
Fewer friction points
than parallelogram
steering
increases road feel
Noise and vibration
transmitted to driver