wheels and tyres ppt

Wheels and tyresFUNDAMENTAL OF AUTOMOBILE ENGINEERING

PROF. KUNALSINH KATHIA

Wheels And Tyres F.A.S

Mechanical Engineering Department http://hjdmech.weebly.com Prepaired By: Prof. Kunalsinh Kathia

Wheel and wheel assembly

Wheel are made by pressing light alloy casting.

The tyre must be strong enough to resist the counter and strong enough.

A dishes steel disc is welded to or is integral with rim.

The assembly bolted to brake-drum makes the wheel demountable.

The rim of the wheel is very important structure, because the tyre is mounted on the rim.

There are basically two type of rims, Drop centre and Flat base rim.

Flat base rim: The flat base rim has its centre portion flat, one side of the rim is removable so tyre can be installed or removed.

This is also known as continues type .

This type of rim contents locking ring to hold the tyres.



Wheel and wheel assembly

Drop center rim: When the center portion of the rim is rolled to a smaller diameter to form a well.

It is known as drop center rim. This rim allows a mounting of tyres by squeezing the beads of the tyre together.

The rim is designed so that the well allows the beads of the tyre to pass over the edge of the opposite side.



Wheel assembly.

It consist of hub,disc,rim,tyre and tube.

The wheels not only support the weight of the wehicle but also supports from the road shocks and jerks.

The rear wheel move the vehicle and front wheel steer it.

All the four wheel must resist the braking stresses and withstand side thrust.

Wheel must be:

Strong enough to absorbe rode stresses.

Capable enough to absorb road shocks.

Able to grip road surface.

Balanced statically and dynamically also.

Light and easily removable.



Terminology Steel Wheels – A very popular

design of wheel. Very strong and cheap to produce.

Alloy Wheels – Attractive and light weight, but can be difficult to clean.

Spoked Wheels – Used on older sports vehicles, but cannot be fitted with tubeless tyres.

Divided rims – the rims are made in two halves which are bolted together, the rims must never be separated while the tyre is inflated.

Split rims – the tyre is held in place by a large circlip, do not remove the tyre unless you have been properly trained

Radial Ply Tyre – the main plies of the tyre run at 90 degrees from one bead to the other.

Cross Ply Tyre – the main plies of the tyre run at 45 degrees from one bead to the other.

Plies – Layers of strong fabric which are built up to give the tyre its strength and shape

Bead – loops of steel which are the anchorage point for the plies.

Tread – this provides the grip with the road surface, the pattern assists in clearing any water away

Side Wall – this connects the beads to the tread of the tyre.



Wheel - Basics

Some vehicles are fitted with alloy wheels that are made of magnesium or aluminium.

The pilot bore fits to the hub.

Most standard wheels are made of steel.

The rim holds the tyre.The well of the wheel allows thetyre to be removed and refitted

The centre section is welded to the rim.

Centre mounting section

Rim

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Pneumatic Tyres

The tyre is a flexible casing, which contains air.

Tyres are manufactured from reinforced synthetic rubber.

The tyre is made from an inner layer of fabric plies, which are wrapped around bead wires at the inner edges.

The bead wires hold the tyre in position on the wheel rim.

The fabric plies are coated with rubber, which is moulded to form the side walls and tread of the tyre. Behind the tread is a reinforcing band, usually made of steel,rayon,or glass fibre. Modern tyres are mostly tubeless, so they have a thin layer of rubber coating inside to act as a seal.



Tyre Construction

Cross – ply tyres are not used on any mass produced modern cars. However, the construction details are useful to show how tyre technology has developed.

Several textile plies are laid across each other, running from bead to bead in alternate directions.

The number of plies depends on the size of the tyre and the load it has to carry.

The same number of plies is used on the crown and the sidewalls.



Tyre Construction Radial – Ply tyres consist of a

carcass ply formed by textile arcs running from one bead to the other.

Each ply which is laid in an arc at an angle of 90 degrees to the direction the tyre rolls.

At the top of the tyre crown (under the tread), there is a belt made up of several plies reinforced with metal wire, laid on top of the carcass ply.

These crown plies, laid one on top of the other, overlap at an angle determined by the type of the tyre.



Tyre Specifications

P 205/55 V R 16

TYPEP - PASSENGERT - TEMPORARY

LT - LIGHT TRUCKC - COMMERCIAL

WIDTH(MILLIMETERS)

145-315

ASPECT RATIO(HEIGHT/WIDTH %)55, 60, 65 70 ETC

TYPEB - BIAS-BELTED

D - DIAGONAL BIAS R - RADIAL

RIM DIAMETER(INCHES) 13, 14 ETC

P 205/55 V R 16P 205/55 V R 16P 205/55 V R 16P 205/55 V R 16P 205/55 V R 16P 205/55 V R 16P 205/55 V R 16

SPEED RATINGB (31 MPH) -

V (150 MPH) -Z (OVER 150 MPH)

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Remember the tyre tread depth must be not less than 1.6mm over the central three-quarters of the tyre and must go all the way round the circumference in an continuous unbroken band with no bald patches anywhere on the tyre tread.

If radial and crossply tyres are fitted to the same vehicle, the radial-ply tyres must only be fitted to the rear.

Cross-ply and radial ply tyres must never be fitted to the same axle.

Tyre pressures must be set to the manufactures recommendations

The tread and side wall must be free from large cuts, abrasions or bubbles



wheels and tyres ppt

Documents

center rim

wheel assembly wheel

flat base rim

type of rim contents

spoked wheels

wheel demountable

rear wheel

wheel steer