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Tire Basic Course
Tire Basic Course
PC Tire Construction
Definition
Tire Basic Course
The tire is the link between the vehicle and the road surface
The tire is transmitting forces between the vehicle and the road in
• vertical direction
spring/ damping function
• horizontal direction (lateral)
guiding function cornering
• horizontal direction (longitudinal)
accelerating/ braking
Tire Basic Course
10
9
8
7
2
5
1
4
5
3
6
11
12
13
14
15
16
17
18
19
10
Innerliner
Carcass Ply
Bead Core
Apex/ Filler
Bead reinforcement
Rimstrip
Sidewall
Belt/ Breaker
Capply
Tread
1 - Innerliner
Tire Basic Course
• The innerliner is a (mostly profiled) sheet of rubber with
a high percentage of Butyl-rubber
• the main purpose of the innerliner is to reduce the air
permeation and to ensure the air-tightness of the tire
• by the fact that the oxidation of the rubber at the belt
edges has direct influence on the durability of a tire, the
innerliner also is directly connected with durability issues
• the innerliner has also an influence on some NVHrelated problems
• in tires with a very small sidewall height the innerliner
must also withstand high shear strain stresses
2 – Carcass (Ply)
Tire Basic Course
• The carcass is made out of layer(s) of textile. This
layer(s) are directed in radial direction (90°)
• the carcass is connecting the bead (which is attached to
the rim) with the crown area and thereby is transmitting
forces between these two areas
• the carcass cannot transmit bending and pressure
forces, only tension forces, the carcass is carrying most
of the load caused by the inner pressure of the tire
• the material for the carcass is mostly Polyester, Rayon
is used for High speed tires (Speed symbol W),
• Changing the carcass material/ number of carcass
3 – Bead
Tire Basic Course
4 – Apex
Tire Basic Course
3/ 4 – Bead/ Apex
Tire Basic Course
• The apex (bead filler) is an extruded, triangle-shaped profile
of rubber with a high shore hardness which is attached
directly on the bead bundle in the preparation process
• the purpose of the apex is to increased the stiffness in the
sidewall and bead area
• a higher/ thicker apex increases driving stability/ steering
precision
• a higher apex adds more masses to the lower sidewall area
and therefore can lead to conflicting results in High speed
durability
• the bead consists of a number of steelcord which (mostly)
are arranged in a square shape
• the main purpose of the bead is to ensure the connection of
the tire with the rim
5 – Bead reinforcements (chipper/ flipper)
Tire Basic Course
• The bead reinforcements are (mostly) layers of textile
attached in the bead area directly to the carcass
• the textile layers are cut under a specific angle (30°, 45°)
related to the carcass, by this carcass and
reinforcement build up a cross-package
• due to this package also bending forces can be
transmitted in this area
• the main purpose of these reinforcements is to stiffen
the lower sidewall/ bead area to influence the driving
behavior (handling!) and the high speed durability of the
tire
• for special applications steelcord is used
6 – Sidewall
Tire Basic Course
• The (combined) sidewall is an extruded rubber profile
consisting of two or more different types of rubber
• the purpose of the upper part, the sidewall is to protect
the carcass against direct mechanical load (e.g.
Curbstones) and against Umwelteinflüsse (UV-rays,
Ozone etc)
• Due to the fact that the carcass cannot transmit bending
and pressure forces, but only tension forces a stiff
sidewall compound can also influence this force
transmission and thereby also influence the driving
behavior
7 – Rimstrip
Tire Basic Course
• the lower part of the sidewall (rimstrip) which is made of
rubber with a higher shore hardness is wrapped
underneath the bead and overlaps the innerliner
• the purpose of this rimstrip is to ensure the correct
seating of the tire on the rim
• additional purpose esp. with a rim protection rib is to
stiffen the lower bead area
8- Belts (breaker)
Tire Basic Course
• The belts are (at minimum) two layers of calandered steelcord
located between the tread/ capply and the carcass
• the belts are directed under a specific angle (22°-34°) which is
reversed between the belts
• thereby the belts together are forming a „package“ of a specific
stiffness in axial and circumferential direction
• by the width, the angle and the construction of the steelcord the
dynamic contour and the footprint and thereby the performance of
the tire can be influenced
• main task of the belts is to stabilize the „crown“ area of the tire and
to transmit forces from the contact patch to the carcass
• the (construction of ) the belts have massive influence on the driving
stability and the durability of the tire
• by every movement through the footprint in a rolling tire but also by
radial and circumferential forces the angles between the belts are
changing. Therefore the separation/ insulation between the belts
and between belt and carcass at the beltedges is necessary.
9 - Capply
Tire Basic Course
• The capply is made out of layer(s) of textile between the tread and
the belt in circumferential direction of the tire
• the capply consists of 1 or 2 sheets nylon „full-capply“ or of small
strips (1 –15mm) which are wound around the belts (jointless/ spiral
capply)
• the material for capply is mostly Nylon, for special applications also
a hybrid material (Nylon/ Aramid) is used
• Nylon has the behavior to shrink under heat. During the curing
process the capply therefore builds up circumferential forces
around the tire.
• The primary function is to reduce the expansion in the crown under
service conditions and reduce the movement of the belt package
and thereby influence the performance of the tire, i.e. High Speed
durability
• the material and the construction of the capply have a direct
influence on the rolling resistance of a tire
10 - Tread
Tire Basic Course
• The tread consists of multiple layers of different types of
rubber which are made by extrusion
• for special application the tread can be wound out of
small strips
• the tread material is influencing the grip between tire
and road and thereby the handling
• further purpose of the tread is to influence mileage and
rolling resistance
• the construction of the rubberlayers has to ensure the
electrical conductivity between the road and the vehicle
Tire Basic Course
#
component
main FUNCTION
MATERIAL
DETAIL
1
innerliner
air tightness
rubber
soft
90°
2
carcass
radial stiffness
textile/cord
(rayon/
polyester)
3
bead core
rim seating, carcass anchor
steel cord
0°
4
apex
handling
rubber
hard
5
bead
reinforcement
enforcement of bead
textile/steel cord
45°/ 60°
6
sidewall
abrasion/UV resistance
rubber
hard
7
belts
lat., circ., rad.
stiffness
steel cords
22°- 36°
8
capply
durability
nylon/ aramid
0°
9
tread
traction/adhesion
rubber
hard
Definition
Tire Basic Course
A steel belted tire is a inhomogeneous
discontinuous Fibre-Cord-Rubber-Compoundconstruction with complex elastic-plastic-viscous
characteristics
under mechanical and thermal stress