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SUSPENSION

101

SAE CLUB IITG1/03/2012

SUSPENSION DESIGNPART 1

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An Automotive Suspension is the system of parts that gives a

vehicle the abil ity to maneuver.

What does a suspension do?The job of a car suspension is to maximize the friction

between the tires and the road surface, to provide steering

stability with good handling

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INTRODUCTION

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Dependent

Independent

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CLASSIFICATION

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SAEINDIA IT-BHU Collegiate Club 4

DEPENDENT SUSPENSION

Solid axle leaf spring

Used in trucks (heavy weight vehicle)

Solid axle Coil spring

(Used in light weight cars)

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INDEPENDENT SUSPENSION

MACPHERSON

STRUTo Basically comprises of a

strut-type spring and shock

absorber combo, which pivots on

a ball joint on the single, lowerarm.

o Strut itself is the load-bearing

member in this assembly, withthe spring and shock absorber

merely performing their duty as

oppose to actually holding the

car up.

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DOUBLE WISHBONE

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INDEPENDENT SUSPENSION

Coil Spring

High travel

Transverse leaf spring

High Ground clearance

Multilink Spring

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OTHER TYPES OF SUSPENSION

Trailing arm

Twin i-beam

Moulten rubber

Four bar

De-dion

http://www.carbibles.com/images/dediontube.jpghttp://www.carbibles.com/images/4barparallel.jpghttp://www.carbibles.com/images/moulton1.jpg

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Pneumatic suspension

Hydrolastic suspension

Ferro fluid suspension

Linear electromagnetic suspension

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OTHER TYPES OF SUSPENSION

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Ride Height

Bump / Droop

Camber

Caster

Toe In / Out

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BASIC SUSPENSION TERMINOLOGY

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RIDE HEIGHT, BUMP & DROOP

Ride Height

The neutral / middle

position of the

Suspension

Bump

When the wheel

moves upwards

Droop

When the wheelmoves downwards

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CAMBER

Affect on pressuredistribution on tire

Generates camberthrust

Dynamic camber inunavoidable

Tires generate morecornering force with asmall amount of

negative camber Camber changes as

suspension moves up(bump) and down(droop)

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CAMBER

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Because of the shape ofThe tire print, the treads entering thetire print closer to the cambered side,Have more time to be stretched laterally.Because the developed lateral

Stress is proportiona lto the lateralstretch,the nonuniform tread stretchingGenerates an asymmetric stressdistribution and more lateral stress willbe Developed on the cambered side. Theresult of the nonuniform lateral stressDistribution over the tire print of acambered tire produces the cambertrustfy in the cambered direction.

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TOE-IN OR TOE-OUT

Toe-in results is

inherently stable

Toe-out is

inherently unstable

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TOE IN AND TOE OUT

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CASTER

Positive caster aids

centering the

steering wheel after

a turn and makesthe fornt tires

straighten quicker

More caster results

in more camber asfront wheels are

turned

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CASTER