38379910-Tyre.ppt
Transcript of 38379910-Tyre.ppt
Selection of Tyres for BAJA Vehicle
by
Rajesh MankarManager – Product Development
J K TYRE AND INDUSTRIES LTD
Sunday, 10th August 2008
Agenda:
History, Tyre Definition & Classification
Function of Tyre
Defining Basic Dimensions
Tyre Construction
Tyre selection criteria based on Vehicle info and performance
New Development Approach
1844 Charles Goodyear invented vulcanized rubber that was later used for tires.
1888 John Dunlop invented the air-filled or pneumatic tires for bicycles.
1895 André Michelin was the first person to use pneumatic tires on an automobile, however, not successfully.
1901 Philip Strauss invented the first successful tire, which was a combination tire and air filled inner tube.
1903 P.W. Litchfield of the Goodyear Tire Company patented the first tubeless tire,
1904 Mountable rims were introduced that allowed drivers to fix their own flats.
1908 Frank Seiberling invented grooved tires with improved road traction.
1910 B.F. Goodrich Company invented longer life tires by adding carbon to the rubber.
History Of Tyre:
What Is Tyre:
Geometrically tyre is a torus reinforced with textile cord ply / fabric or steel
carcass enclosing bead ring.
Mechanically it is a flexible membrane pressure container
Structurally it is a high performance composite
Chemically a material composed of long chain of macromolecules
TYRE SIZE DESIGNATION:
A Tyre is generally designated by its nominal cross section code followed by the nominal rim diameter code.For radial tyres,
145/80R13
Section width (mm) Aspect Ratio Nominal Rim Dia (inch)
Tyre Size Designation:
Enveloped Dimension:
145/80R13
Section Width – 145 mmAspect Ratio – 80 Rim Diameter – 13”
Aspect Ratio Section Height
Section Width
Outer Diameter = (2 x Section Height in mm) + Rim Diameter in mm
Section Height = 145*0.8 = 116 mm
Outer Diameter = (2*116) + (13*25.4) =562.2 mm
Basic Tyre Dimensions:
Tyre Section
Function Of Tyre:
Provide Load Carrying Capacity
Provide Cushioning and dampening
Transmit driving and braking torque
Provide Cornering force
Provide floatation and dimensional stability
Resist abrasion
Generate steering response
Have low Rolling Resistance
Provide minimum noise and minimum vibration
Be durable throughout and expected life spam
Tyre Construction:
BIAS RADIAL
TUBE TYPE TUBELESS
Contd…
Tyre Construction:
Cord strips are arranged diagonally to the
centerline of the tire.
Positive Qualities - strengthens the sidewall
and stabilizes the tread area for contact patch.
Negative Qualities – Builds up excessive heat;
very stiff and hard riding; get flat spots after
sitting in one spot and cooling down.
Plies are laid at 90 degree angles to centerline of tire
More sidewall movement and a smoother ride
Last longer than bias ply tires
BIAS RADIAL
Tyre Construction:
RADIAL
Tyre Construction:
BIAS
Tyre Construction:
ADVANTAGE OF RADIAL TYRES
50 - 100% LONGER LIFE - REDUCED COST PER KILOMETER
5 - 10% FUEL SAVING
PUNCTURE RESISTANT - LESS DOWN TIME
RIDING COMFORT AND REDUCED CARGO DAMAGE
EXCELLENT HIGH SPEED CAPABILITY
EXCELLENT DAMPENING OF VIBRATIONS
EXCELLENT TRACTION & BRAKING ON BOTH DRY AND WET ROAD
Tyre Construction:
Tubeless Technology
A tubeless tyre is designed with a Halobutyl liner on the inner side which is applied from bead to bead.
The Bead contour of tubeless tyres are designed to provide a self sealing mechanism between the
tyre and rim.
Lower Rolling resistance
Better handling Characteristics at high speeds
It is also reported, that air leakage after puncture
is slower in tubeless tyres than tubetype tyres thus
making tubeless tyres safer.
ADVANTAGE OF TUBELESS TYRES:
A tube Type tyre running at reduced
pressures generates more heat and is more
prone to damage.
A tube type tyre is often easier to repair in
the bush than a tubeless one, because they
are easier to remove from the rim and are
much easier to re- inflate
Tubes do not strengthen the tyre or help
prevent punctures.
Tube Type
Tyre selection criteria based on Vehicle Application and performance
Passenger Car
SUV
MUV
Light commercial Vehicle
Heavy commercial Vehicle
Based on Vehicle Application:
Based on Vehicle Dimensions / Load / Speed:
Wheel Base Tread Ground Clearance
FAW / RAW
Kerb Weight
Gross Vehicle Weight
Empty Vehicle Weight
Pay Load
Load Distribution
Tyre Selection Criteria Based on Performance:
Safety- Max. driving safety under various conditions (dry, wet, winter, etc.)
Handling-Tire Characteristics- Cornering
Economics- Mileage- Rolling Resistance
Comfort- Mechanical Comfort (flat spot)- Acoustic Comfort
Effect of component on Tyre Performance:
HYSTERESIS LOSS – Rubber
ASPECT RATIO
RIM WIDTH
TYRE SIZE
TYRE TYPE
TREAD PATTERN
TREAD RADIUS
TREAD THICKNESS
TREAD DEPTH
CORD ANGLE
NUMBER OF BODY PLIES
CONSTRUCTION
ROAD TEXTURE AND ROUGHNESS
AERODYNAMIC DRAG
NOISE
AIR CAVITY PUMPING
INFLATION PRESSURE
EFFECT OF SPEED
EFFECT OF LOAD
EFFECT OF TEMPERATURE
EFFECT OF INNER TUBE
Internal Factor External Factor
Feel the power of FEA SimulationFeel the power of FEA SimulationFeel the power of FEA SimulationFeel the power of FEA Simulation
A Simulation showing strain energy Distribution under loading
An FEA simulation revealing Inter carcass pressure acting Inside the tyre
Predictive Methods to Optimize Tyre Design:
Tyres determine to a great extent the dynamic behavior of road vehicles. Our attempt is to assist in bringing optimized synergy between the mechanical characteristics of tyre in contact with the road & the mechanics of the vehicle so that tyre-vehicle system operates safely under any circumstances & in a way that is satisfactory to the driver.
Predictive Methods to Optimize Tyre Design:
Force & Moment Test Machine
Other Methods to Optimize Tyre Design:
Tyre Selection Criteria Based on Performance:
Rolling Resistance
Mechanical Energy converted into Heat by a tire moving for a unit distance on the roadway as a result of the rotation and the deformation of the tire
Energy Consumed per unit distance of travel as a tire rolls under load
Resistance to Motion
The amount of energy required overcoming the friction between the tyre and road surface.
The RR of a tire is responsible for
14.4% of the total vehicle energy loss.
For passenger and light truck,
Improvement in rolling resistance of
10% - Fuel efficiency increased by 0.5 ~
1.5% and for heavy truck fuel efficiency
increased by 1.5 ~ 3.0%
Contd…
Tyre Selection Criteria Based on Performance:
% Contribution to RR
26%
2%
2%
7%
7% 8
%
48%
<2%
Tread
Belt
Inner Liner
Sidewall
Ply
Filler
Rim Strip
Bead &Chafer
Rolling Resistance
Rolling Resistance Testing Machine
Tyre Selection Criteria Based on Performance:
Tyre Traction
Traction performance can be characterized in many ways,
including braking, acceleration, cornering, controllability,
and grade climbing. Though all factors are important, the
single best indicator of tire performance is braking distance
and deceleration.
PARAMETERPARAMETER TRACTION (WET & DRY)
TARGETTARGET IMPROVED TRACTION WITHOUT
SACRIFICING TREAD LIFE
PRIORITYPRIORITY INTERMEDIATE
PRIMARY APPROACHPRIMARY APPROACH TREAD COMPOUND OPTIMIZATION
SECONDARY APPROACHSECONDARY APPROACH CASING DESIGN OPTIMIZATION
IMPORTANTIMPORTANT TO CONTROL TENDENCY OF WANDERING & STEERING PULL WHILE BRAKING OEMs ARE EMPHASIZING THE NEED TO ACHIEVE A STABLE CONTACT PATCH WHICH DOES NOT CHANGE ITS CENTRE DURING BRAKING
LoadDirection of travel
Traction
Tyre Traction – Subjective & Objective Evaluation
Tyre Selection Criteria Based on Performance:
Tyre Wear
Factors affecting Tyre Wear
Improper Vehicle toe, camber,caster, drive axle parallelism andperpendicularity are important factorstire wear patterns.
PARAMETER TREAD MILEAGE (WEAR)
TARGET FURTHER IMPROVEMENT REQUIRED
PRIORITY INTERMEDIATE
PRIMARY APPROACH TREAD DESIGN / DEPTH OPTIMIZATION
SECONDARY APPROACH TREAD FORMULATION OPTIMIZATIONINCREASED USE OF POLYBUTADIENE AND OPTIMIZED SOLUTION SBR
Structure Pressure Imaging and
Analysis
Pressure Mapping
Pressure Application
Foot Print Pressure Distribution study revealed
higher pressure at Shoulder blocks than at center.
Fujifilm Footprint pressure distribution study
Tyre Wear Predictive Methods:
Thermography
Measurement of surface temperature in the tyre using a thermo graphic camera and fine tuning the related parameters during the development
process
Min Temperature – 62.69Max Temperature – 72.56
T h e r m o t e k n i x VisIR 15:00:51 03/05/2004 e : 1.00 Bg : 20.0°C
-20.03
500.00
48.74
72.47Celsius
50.00
52.00
54.00
56.00
58.00
60.00
62.00
64.00
66.00
68.00
70.00
Line 1Length11
Area 1Max. Avg. Min.72.56 67.81 62.69
Img480: Line 1
Te
mp
era
ture
/ °C
Distance / Meters
48.751.153.555.858.260.663.065.467.770.172.5
0 5 10 15
Min Temperature – 58.19Max Temperature – 67.58
T h e r m o t e k n i x VisIR 15:04:21 03/05/2004 e : 1.00 Bg : 20.0°C
-20.03
500.00
45.00
70.00Celsius
50.00
55.00
60.00
65.00
Line 1Length11
Area 1Max. Avg. Min.67.58 62.97 58.19
Tyre Wear Predictive Methods:
Cornering Stiffness Testing
Tyre Selection Criteria Based on Performance:
Tyre Ride & Handling Performance
PARAMETER RIDE & HANDLING PERFORMANCE
TARGET FURTHER IMPROVEMENT REQUIRED
PRIORITY INTERMEDIATE
PRIMARY APPROACH PATTERN DESIGN ENGINEERING (NOISE) CASING DESIGN ENGINEERING (CONSTRUCTION, MATERIALS & CONTOUR IN ORDER OF PRIORITY)
SECONDARY APPROACH TREAD COMPOUND OPTIMIZATION(INITIATION OF VERTICAL ENGINEERING IMPLEMENTATION (VEHICLE & TYRE DESIGNERS WORKING CLOSELY FROM THE INCEPTION STAGE))
Tyre Ride, Comfort & Handling Performance
Tyre Ride, Comfort & Handling Performance
Breaking StrengthStiffness Test Station
2D - Pattern3D - Model Marking
Hand Carving
Tyre testing
fitted on vehicle
Rapid Prototyping
Functional Parameters:
Rubber Compound and Chemicals: a) Natural Rubber b) Synthetic Rubber c) Carbon Black d) Silica e) Fabric f) Steel Cords
Functional Parameters:
RIB PATTERN : The pattern along the circumference of the tyre
Good points : Lower rolling resistance. Good directional stability and steering control thanks to lateral resistance. Suitable for sustained high speeds thanks to low heat generation.
Bad points : Poor braking & acceleration grip on wet roads. Stress caused by flex means tread is more susceptible to cracking.
Use : For paved road surfaces and the steering wheels of trucks or buses
LUG PATTERN : The groove pattern perpendicular to the circumference of the tyre
Good points : Excellent braking & driving power. Superior traction.
Bad points : Noisy at high speed. It's not suitable for high speed driving because of high rolling resistance.
Uses : For dirt roads, rear wheels of buses, industrial vehicles and dump trucks .
Tread Pattern:
Functional Parameters:
Tread Pattern:
SEMI-LUG PATTERN : The combination of Rib-shape & Lug-shape
Features : The rib in the centre provides directional control whilst the shoulder lug gives good braking & driving power.
Uses : Good for both paved and dirt roads. Usually used in both front & rear wheels of trucks and buses.
BLOCK PATTERN : The pattern of independent block which the groove is connected with each other
Good points : Good steering control and stability on snow covered and wet roads. Good water dispersal properties on wet roads.
Bad points : Tyre wear is heavy as tread blocks are finer.
Uses : Suitable for winter or all-season passenger car tyres. Suitable for back-wheel of Radial tyre of ordinary car .
Functional Parameters:
Tread Pattern:
ASYMMETRIC PATTERN : Tread pattern differs on either side
Good points : Good for high speed cornering thanks to greater contact area. Reduces tread-wear on outside of tyre.
Bad points : You must position them the right way around.
Uses : High performance and motorsport tyres.
DIRECTIONAL PATTERN : Lateral grooves on both sides point the same direction.
Good points : Good driving force and braking performance. Good water dispersal means good stability on wet roads. Correct choice for fast driving styles.
Features : mounted in direction of tread pattern.
Uses : the passenger car tyre for high speed usage.
Functional Parameters:
TreadBelt and BreakersCap Ply/ Prot Ply CarcassSide WallBeadChaferFiller
Tyre Components:
Functional Parameters:
Tread
Tread is the wear resistance component of the tyre, when it is contacting with the road. It must also provide traction, wet skid and good cornering characteristics with minimum noise generation and low heat buildup. It is the part through which braking, driving and cornering forces are transmitted.
These are short plies of rubber coated steel cut at an angle and are positioned centrally between the tyre casing and tread to strengthen carcass against impacts.
Belts
Cap Ply
It is placed in the crown area just below the tread rubber. It provides cut resistance protection to the underlying belts and carcass plies.Enhances high-speed suitability.
Functional Parameters:
Carcass
Rubber bonded cord structure of a tyre integral with the bead, which provides the required strength to carry load.
Sidewall
Part of the tyre between bead and tread which flexes in service. Protects the casing from side scuffing, control vehicle and ride characteristics and assist in tread support
Bead Core
A bead should hold the tyre against the rim and should avoid the movement of the tyre relative to rim. The shape and contour of the bead conforms to the flange of the rim, thus preventing from rocking or slipping on to the rim.
Functional Parameters:
Filler
Chafer
Gives steering precisionImproves comfort
To prevent chafing action between bead and rim. Their purpose is to protect the carcass plies from damage when mounting or dismounting and to reduce the effects of wear and chafing between the wheel and thetire bead