Intro to Tyre Component Design & Testing.pdf

INTRODUCTION TO TIRE COMPONENT FUNCTION, DESIGN & TESTING

Eddie Young

TIRE BASICS • PROVIDES THE VEHICLE-TO-ROAD INTERFACE •

SUPPORTS VEHICLE LOAD - AIR PRESSURE

•

PROVIDES ROAD SURFACE FRICTION FOR: BRAKING ACCELERATING STEERING CORNERING

IN: DRY WET SNOW MUD/SAND/ROCKS

•

ABSORBS ROAD SURFACE IRREGULARITIES

•

PROVIDES SPECIFIC DRIVER ‘FEEL’ and RESULTING CONTROLLABILITY OF VEHICLE

COMPONENTS OF A RADIAL TIRE

COMPONENTS OF A RADIAL TIRE

• INNERLINER - AIR AND MOISTURE IMPERMEABILITY - AIR RETENTION

• BEAD FILLER - STIFFNESS WHICH AFFECTS RIDE AND HANDLING

• ABRASION GUM STRIP - RESISTS ABRASION FROM RIM CONTACT

COMPONENTS OF A RADIAL TIRE

• STEEL BELT SKIM - ADHESION TO BRASS PLATED STEEL - TEAR RESISTANCE - LONG TERM AGING RESISTANCE

• BODY PLY SKIM - ADHESION SYSTEM FOR BODY PLY

• BEAD INSULATION - ADHESION TO BRONZE PLATED BEAD WIRE

COMPONENTS OF A RADIAL TIRE

• UNDERTREAD - AIDS IN ADHERING THE TREAD PACKAGE TO THE CARCASS - IMPROVES OVERALL TIRE DURABILITY - ABILITY TO ADHERE TO BRASS PLATED STEEL

• BELT WEDGE - REDUCES THE INTERPLY SHEAR STRAIN AT THE BELT EDGES - IMPROVES DURABILITY

• SHOULDER INSERT - OPTIMIZES BELT/CARCASS CONTOUR - INHIBITS STRAIN RELATED TEAR ALONG THE BODY LINE

COMPONENTS OF A RADIAL TIRE

• SIDEWALL - COVERS THE FABRIC BODY; PROVIDES: - PROTECTION AGAINST FLEX FATIGUE & WEATHER INDUCED CRACKING - ABRASION RESISTANCE - TIRE APPEARANCE - DECORATIVE TREATMENT – WHITE - MUST RESIST ENVIRONMENTAL ATTACK - UV - WATER - OXYGEN / OZONE - HEAT - DIRT

COMPONENTS OF A RADIAL TIRE

• TREAD - LARGE INFLUENCE UPON FUEL ECONOMY - PROVIDES WEAR, CHIP/TEAR RESISTANCE - PROVIDES WET/DRY/SNOW TRACTION - PROVIDES HANDLING

• SUBTREAD - IMPROVES FUEL ECONOMY - IMPROVES OVERALL TIRE DURABILITY - CAN IMPROVE RIDE COMFORT

TREAD RUBBER CONFIGURATIONS

2 PIECE. S/W OVER TREAD

2 PIECE. TREAD OVER S/W

2 PIECE. TOS +BASE

3 PIECE. CAP/WING/BASE

COMPONENTS OF A RADIAL TIRE

EFFECT of STEEL BELTS on INFLATED SHAPE

WITHOUT BELT

WITH BELT

STEELCORD 1X5 1X3 2+2 2+5

6 OVER 3

STEEL BELT CROWN ANGLE

This angle

Changing the belt angle or wire specification are effective ways to tune the tire for steering, handling or ride performance.

or this angle depends on tyre manufacturer

COMPONENTS OF A RADIAL TIRE

BELT WIDTH 1st Belt Ply 2nd Belt Ply

Narrow Good for: Comfort / Rolling Resistance / Weight Reduction Belt Edge “Stagger”

Wide Good for Handling / High Speed

TYPICAL EFFECTS OF INCREASED BELT WIDTH

Grv Wander

Wear 120

Irreg Wear

100

Resist.

1K Gravel

80 Durab

Dry Hndl'g

60 40

H.S.

Wet Hndl'g 20 0

F&M

Snow Hndl'g

RSAT

Ride

Wght

Noise R.R. Snow Trac

Dry Trac Wet Trac

BLUE – STANDARD BELT WIDTH: RED – INCREASED BELT WIDTH

BELT REINFORCEMENT (Circumferential Nylon @ 0 degrees) oooooooooooooo oooooooooo

ooooooo

Cross section thru edge strips

EDGE STRIPS

CAP PLY

BODY MATERIAL & CONFIGURATION •

•

• •

• •

Material Type e.g.  Rayon (Europe; high performance.)  Polyester (USA; lower performance.)  Nylon (no longer common) Cord Construction e.g. 900/2, 1000/3  Denier (900, 1000, 1500 etc)  Number strands/cord (/2, /3 etc) Cord Concentration  Number of cords/unit length Number of Plies (1, 2, 3 etc)  Depends on size & application Ply Width(s)  For turn-up height Cord Angle (nominally 90 deg. but up to 5 deg. less)

2 Ply (2+0)

2 Ply (Quick Two)

Body Ply Endings

Other Constructions: 1+0 1+1 2+1 etc.

BEAD FILLER CONFIGURATION • Height • Volume • Material

Small Filler “soft “spring effect Good for Comfort (except “Damping)

Note: Filler also called “Apex” in the industry Hint: Think of the tyre sidewall as a spring

Large Filler “hard” or “stiff” spring effect Good for Handling/Stability

TREAD WIDTH

Narrow with “Round” Shoulder Wide with “Square” Shoulder

FOOTPRINT SHAPE Footprint Ratio = Shoulder Length Relative to Center Length

CL

CL

SL

Convex or Round FP. Low FP Ratio

Flat or Square FP. High FP Ratio

Footprint shape is effective way to tune the tyre CL = Centre Tread Length.

SL

SL = Shoulder Tread Length

TREAD PATTERN DESIGN

 No. Ribs  Groove Spacing  LGSD  Void  See-Thru  Shldr Slots  Element Orient.  No. Pitches  Tie Bars

NOISE TREATMENT

Same fundamental tread element shapes produced in different element sizes and located around the tyre circumference according to computer optimised layout for noise reduction.

TIRE DESIGN

CONSTRUCTION: COMPONENT VARIABLES PERFORMANCE TRADEOFFS

PROFILE: DIMENSIONAL VARIABLES PERFORMANCE TRADEOFFS

TREAD PATTERN: FEATURE VARIABLES NOISE TREATMENTS PERFORMANCE TRADEOFFS

TIRE DEFLECTION

THE INTERNAL AIR PRESSURE DOES THE WORK JUST AS THE AIR, IN THE COMPRESSER TANK, NOT THE TANK, DOES THE WORK OF RUNNING YOUR AIR TOOLS. TIRE LOAD CAPACITY IS PROPORTIONAL TO THE INTERNAL SURFACE AREA OF THE TIRE AND THE INTERNAL AIR PRESSURE

TIRE LOAD CAPACITY CAN BE INCREASED BY INCREASING THE INTERNAL SURFACE AREA OF THE TIRE (I.E. MAKE THE TIRE BIGGER) TIRE LOAD CAPACITY CAN BE INCREASED BY INCREASING THE INFLATION PRESSURE

TYPICAL OE TIRE DEVELOPMENT PROCESS

OEM Tests

PERFORMANCE TARGETS Wear Flat Spot

100

Irreg Wear

90

Resist.

80

1K Gravel

70

60

Grv Wander

Dry Hndl'g

50

40

30

H.S.

Wet Hndl'g

20

10

0

F&M

Snow Hndl'g

RSAT

Ride Wght

Noise R.R.

Dry Trac Wet Trac

NOISE

RIDE

DRY HANDLING

HANDLING TERMS

TYRE PERFORMANCE REQUIREMENTS Snow Handling Wet Handling Braking

Groove Wander

Harshness Damping

Lane Change

RoadNoise

Pattern Noise

Durability

Dry Handling

Highway Braking

INTRODUCTION TO TIRE TESTING

TYPICAL INDOOR TESTS  MEASUREMENT o

MASS, SECTION, OD, SKID DEPTH o DEFLECTION  BAR STIFFNESS  FUNDAMENTAL STIFFNESS  RADIAL  LATERAL  CIRCUMFERENTIAL FOOTPRINT BEAD COMPRESSION BEAD UNSEATING ◦ HIGH SPEED ◦ ROLLING RESISTANCE  1.7 METER DRUM (SAE)  TWIN ROLL

       

FORCE & MOMENT RSAT RPM NOISE AIR PERMEATION TIRE RESISTIVITY UNIFORMITY DURABILITY

◦ GENERAL ◦ AREA SPECIFIC

 WEAR  ENVELOPMENT POWER

TYPICAL OUTDOOR TESTS • COMFORT / NVH • HANDLING – WET – DRY – SNOW – MUD • TRACTION – WET – DRY – SNOW – HYDROPLANING • RPM/RPK

• RAPID AIR LOSS • RIM ROLL OFF • DURABILITY – CHIP TEAR • WEAR – SHOULDER WEAR – IRREGULAR WEAR – HIGH SPEED WEAR – CONSUMER WEAR