Steering systems

Steering systems

Parts and function

copyright 2011 - eric jaromin

Steering system
components
 Steering wheel, column and shaft –
driver inputs
 Steering gear – changes direction –
rotating steering wheel into linear motion
 Steering linkage – connects steering
gear to steering arms
 Ball joints – allows movement of steering
components and suspension

Steering


Steering wheel

 Attaches to steering column and shaft by
1 or more fasteners, most single nut
 Have an interference fit on the shaft –
very tight fit, may need a puller
 May contain an airbag assembly, radio
controls, cruise controls, etc


Steering wheel


Puller


Steering column
 Contains and supports the steering shaft
 May have a tilt mechanism
 May have telescoping mechanism
 Also houses ignition switch
 May be designed to collapse during front
impact – has plastic or soft metal rivets
that are easily damaged or broken from
improper use or removal

Steering column


Steering column
coupler
 Steering column couplers allow pivot
points in the column
 Like a universal joint
 Loose or worn couplers will result in a
loose steering feel, vibration, noise, or
sticky steering feel


Steering column
coupler


Impact
 If the vehicle is involved in a front impact,
always inspect the steering column and
wheel
 Squeaking, chirping or rubbing sounds
indicate damage
 Catching, binding and play indicate
damage
 Especially if the airbag deploys!

Steering ratio
 Steering ratio is a measurement of how many turns of
the steering wheel it takes to go from a full lock to the
other full lock
 Basically how many turns from all the way left to all the
way right
 Also measured from the center (straight) to a full lock
turn
 Fast ratio is 3 turns lock to lock
 Slow is about 4 or 5 times lock to lock
 15:1 ratio – wheels move 15deg for 1 deg of steering
wheel movement

Variable ratio steering


Steering gear systems

 Recirculating ball
 Rack and pinion
 Power assist
 Electronic assist


Recirculating ball

 Recirculating ball is used on trucks in
modern vehicles
 Used on most vehicles prior to 1980 and
the use of front wheel drive
 Uses balls on a worm gear
 Has a pitman arm


Recirculating ball
 Balls inside the gear ride inside guide
paths
 Move from one end of the ball nut
through guides, back to the bottom of the
housing
 Uses a Parallelogram Linkage steering
arm system
 Pitman arm moves steering tie rods

Recirculating ball


Rack and pinion
steering
 Uses a rack and pinion gear
 Pinion meshes with a gear on end of
steering shaft
 As gear rotates, pinion rotates and
moves rack left or right


Rack and pinion


Steering linkage

 Steering linkage is anything connected to
the wheels and the steering gear
 Tie rods
 Steering arms
 Steering knuckles
 Ball joints


Steering linkage


Tierods

 Tierods are attached to pivot points on
each front wheel
 The other end is attached to the steering
gear or rack
 Allows for suspension movement
 Used to adjust TOE of the car – tires face
in / or out / when driving straight


Tierods


Steering arms

 Tierods attach to the front wheels at the
steering arms
 The steering arm is attached to the
steering knuckle, which includes the
spindle
 Used to get proper steering angle during
turns


Steering arms


Steering knuckle and
spindle


Ball joints

 Allow suspension movement up and
down, as well as turning movement
 Located in control arms – in lower, as
well as upper control arm if so equipped
 Wear items – need replacement
periodically


Ball joints


Steering designs

 Parallelogram – used on cars with
recirculating ball gear steering
 Rack and pinion – used on cars with a
steering rack and pinion gear


Parallelogram

 Uses tierods connected to a center link
 Uses a pitman arm to move steering
linkage
 Also uses an idler arm to support the
linkage on the passenger side


Parallelogram steering


Pitman arm


Rack and pinion

 Fewer moving parts than the recirculating
ball
 Smaller and more compact
 Can be a center link type as well


Power steering
 Used to aid in steering
 Can be hydraulic – uses a pump driven by the
engine, or an electric motor, to pump fluid
through the power steering rack/box to aid
driver in turning the steering wheel
 Can be electric – uses electric motor mounted
on rack/box to help driver turn the steering
wheel


Power steering


Electronic power
steering


4 wheel steering

 Used by some manufacturers to aid
handling
 Front wheels do most of the steering
 At low speeds, rear wheels steer
opposite front to tighten turning radius
 At high speeds, rear wheels turn with
front to improve handling and cornering


4 wheel steering

 Can be hydraulic or electric
 Front steering is usually “normal” power
steering
 Rear wheel steering can be driven
hydraulically or by electric motor


4 wheel steering

 3000GT VR4 All Wheel Steering demo – Yo


Steering systems

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