Team:Brasil-USP/Project/TireComposition

The Tire

Project

    Tire is one of the most important components of any motor vehicle, supporting its weight, its cargo and making direct contact with the ground. It is responsible for turning the motor power into traction, as well as for the stability of the vehicle and its efficiency of braking.
    Tires are mainly composed of different types of rubber, fillers - such as clay and silica - carbon black and minerals and chemicals that speed up the vulcanization process, making these materials very difficult to recycle. Each of the different rubber types present very different properties which require great precision in manufacturing.

Tire's Composition

The table below shows the approximate composition of Passenger Car, Lorry and OTR Tires.
Ingredient
Passenger Car Tire
Lorry Tire
OTR Tire
Rubber/Elastomers1
47%
45%
47%
Carbon Black2
21.5%
22%
22%
Metal
16.5%
25%
12%
Metal
16.5%
25%
12%
Textile
5.5%
--
10%
Zinc Oxide
1%
2%
2%
Sulphur
1%
1%
1%
Additives3
7.5%
5%
6%
Carbon-based materials, total4
74%
67%
76%
1 Lorry & OTR tyres contain higher proportions of natural rubber than passenger car tyres.
2 Silica replaces part of the carbon black in certain types of tyres
3 Some of the additives include clays, which may be replaced in part in some tyres with recycled rubber crumb from waste tyres
4 These approximate totals would be slightly higher if clays were replaced by recycled crumb rubber from waste tyres

Tire's Structure

Let´s take a look inside the tires:

Inner Liner

The inner liner has the function of holding high-pressure air inside. It is composed of rubber layer with low air permeability, and generally consists of butyl, synthetic rubber, or polyisoprene type.

Bead

The bead is in contact with the rim, then, in the case of sudden reduction of air pressure while driving, the tire will not become loose from the rim. The bead is made up of various parts including the bead wire, core, rubber and flipper.

Carcass

The carcass is the framework of the tire, its most important part. The carcass is made of cord and has the function of absorbing the tire’s internal air pressure, weight and shock.

Breaker or Belt

The breaker has the function of absorbing external shock and helps prevent any tread injury from coming into direct contact with the carcass. In order to do that, the breaker is placed in between the tread and carcass and it is made of chord. Also, the breaker prevents the separation from the rubber layer and the carcass.
The belt is a strong reinforcement layer placed in between the tread and carcass in radial tires. The belt’s functions are similar to the breaker’s but it also tightens the carcass reinforcing the strength of the tread.

Tread

The tread is highly resistant to protect the carcass and belt. It consists of a thick layer of rubber which comes into direct contact with the road surface. Besides, rubber with strong anti-inner abrasion features is used to increase tire’s driving lifespan.

Sidewall

The sidewall has the function of protecting the carcass on the inside and providing a comfortable riding experience due to its flexibility during driving.

Shoulder

The shoulder dissipates heat that is accumulated inside tires while driving.

Referências

1.http://www.wrap.org.uk/sites/files/wrap/2%20-%20Composition%20of%20a%20Tyre%20-%20May%202006.pdf
2. Composition of main materials used in automobile tires in Japan in 2012.
Source: Kunioka, Masao; et al; “Biobased Contents of Natural Rubber Model Compound and Its Separated Constituents”; Polymers 2014, 6(2), 423-442; doi:10.3390/polym6020423
http://www.mdpi.com/2073-4360/6/2/423/htm 3. http://www.hankooktire.com/global/tires-services/tire-guide/tire-structure.html

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