presentation on suspension

8/14/2019 presentation on Suspension

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Types OfSuspensions

McPhursunStrut

DoubleWishbone


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INTRODUCTION

The job of a car suspension is tomaximize the friction between

the tires and the road surface, toprovide steering stability with

good handling and to ensure thecomfort of the passengers .

Apart from your car's tyres andseats, It also prevents your carfrom shaking itself to pieces.
http://auto.howstuffworks.com/tire.htmhttp://auto.howstuffworks.com/tire.htm


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The components of the suspension system perform six basic functions:

1. Maintain correct vehicle ride height

2. Reduce the effect of shock forces

3. Maintain correct wheel alignment

4. Support vehicle weight

5. Keep the tires in contact with the road

6. Control the vehicles direction of travel


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Components Of Suspension

Springs

ShockAbsorbersAntirollBars


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SpringsThese come in three types. They are coil springs, torsion bars and leaf

springs .

1. COIL SPRINGS - This is the mostcommon type of spring and is, inessence, a heavy-duty torsion barcoiled around an axis. Coil springscompress and expand to absorb themotion of the wheels.

2. LEAF SPRINGS - This type of springconsists of several layers of metal(called "leaves") bound together toact as a single unit.Leaf springs were

first used on horse-drawn carriagesand were found on most Americanautomobiles until 1985. They are stillused today on most trucks andheavy-duty vehicles.


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3. TORSION BARS - Torsion bars use the twisting properties ofa steel bar to provide coil-spring-like performance. One end

of a bar is anchored to the vehicle frame. The other end isattached to a wishbone, which acts like a lever that movesperpendicular to the torsion bar. When the wheel hits abump, vertical motion is transferred to the wishbone andthen, through the levering action, to the torsion bar. Thetorsion bar then twists along its axis to provide the spring

force


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Shock Absorber

A shock absorber is basically an oil pump placedbetween the frame of the car and the wheels.The upper mount of the shock connects to theframe (i.e., the sprung weight), while the lowermount connects to the axle, near the wheel

(i.e., the unsprung weight). In a twin-tubedesign, one of the most common types of shockabsorbers, the upper mount is connected to apiston rod, which in turn is connected to apiston, which in turn sits in a tube filled withhydraulic fluid. The inner tube is known as thepressure tube, and the outer tube is known asthe reserve tube. The reserve tube storesexcess hydraulic fluid.

Shock absorbers work in two cycles -- thecompression cycle and the extension cycle


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Anti Roll BarsAnti-roll bars do precisely what their name

implies - they combat the roll of a car onit's suspension as it corners. The anti-rollbar is usually connected to the front,lower edge of the bottom suspension

joint. It passes through two pivot pointsunder the chassis, usually on thesubframe and is attached to the samepoint on the opposite suspensionsetup. For example, if you're cornering tothe left, the car body rolls to the right. Indoing this, it's compressing thesuspension on the right hand side. With agood anti-roll bar, as the lower part of thesuspension moves upward relative to thecar chassis, it transfers some of thatmovement to the same component onthe other side.


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Front Suspension Types

independent systems

Semi-independent systems


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Front suspension - independentsystems

So-named because the front wheel's suspensionsystems are independent of each other (except

where joined by an antiroll bar) These came intoexistence around 1930 and have been in use in

one form or another pretty much ever since then.


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McPherson Strut

This transfers the load-bearing capability ofthe suspension almost entirely to the upperarm and the spring mounts.The lower arm inthis instance becomes a control arm. Thisparticular type of system isn't so popular incars as it takes up a lot room.


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Double wishboneThis is a type of double-A or double wishbonesuspension. The wheel spindles are supported by anupper and lower 'A' shaped arm. In this type, the lowerarm carries most of the load. If you look head on atthis type of system, what you'll find is that it's a veryparallelogram system that allows the spindles to travel

vertically up and down. When they do this, they alsohave a slight side-to-side motion caused by the arc thatthe wishbones describe around their pivot points. Thisside-to-side motion is known as scrub. Unless the linksare infinitely long the scrub motion is always present.There are two other types of motion of the wheelrelative to the body when the suspension articulates.The first and most important is a toe angle (steerangle). The second and least important, but the onewhich produces most pub talk is the camber angle, orlean angle. Steer and camber are the ones which weartyres.


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Rear Suspension Types

dependent systems (linked)

independent system


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Rear suspension - dependent systems

If a solid axle connects the rearwheels of a car, then the suspensionis usually quite simple -- based either

on a leaf spring or a coil spring.


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Rear suspension - independentsystems

If both the front and back suspensions areindependent, then all of the wheels aremounted and sprung individually, resulting

in what car advertisements tout as "four-wheel independent suspension."


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