Post on 16-Jul-2015
transcript
What is a TYRE?
A tire (U.S. English) or tyre (British English) is a
ring- shaped vehicle component that covers the
wheel’s rim to protect it and enable better vehicle
performance. Most tyres, such as those for
automobiles and bicycles, provide traction
between the vehicle and the road while providing
flexible cushion that absorb shock.
The materials of modern pneumatic tyre are
synthetic rubber, natural rubber, fabric and wire,
along with carbon black and other chemical
compounds.
They consist of a tread and a body.
The tread provides traction while body provide containment
for a quantity of compressed air.
Tyre is used to transmit the driving and braking forces t o the
road.
It is also used to provide concerning power to smooth
steering
Why Compressed Air in a Pneumatic
Tyre?
A pneumatic tyre is comprised of an airtight inner core that filled with compressed air.
The compressed air inside the tyre maximizes the tire’s load-carrying capacity, absorb shock’s, and provide resistance against cutting and abrasion.
The compressed with in the tyre is greater than the atmospheric pressure outside the tyre. As a result, the tire is able to remain inflated even under the weight of the vehicle. It is actually the tyre’s air pressure that protects the tyre from deformations and general wear and tear and gives the tire its cushioning effect.
Introduction Tweel is an “airless”, or “non-pneumatic” tyre
that is the hope for future automobiles. This may seems like bicycle wheel, but unlike one.
Tweel tire aims at performance levels beyond those possible with conventional pneumatic technology because of its shear band design, added suspension, and potentially decreased rolling resistance.
As the Tweel is extremely resistant, wear working on a range of other application including smaller earth mover and military vehicle.
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The name “Tweel” is the
contraction in English of
“ t yre” and “W h eel”. Rather
than a wheel + a tyre , we
now have a single product
TWEEL. Mounting and
removal operation will be
simpler. To start with, Tweels
could be fitted on vehicles
with small wheels, such as
wheelchairs, thus
substantially improving the
mobility of disabled people.
What makes tyre “AIRLESS”?
The structure of SPOKES stretching along the
inner side of tyres supporting the weight of the
vehicle.
A synthetic resin that becomes flexible when
heated, can be processed into a variety of
shapes, and become hard when cooled.
The changes from heating and cooling can
generally repeated , making it easy to both
mold and recycle the material
Why Tweel? The heart of Tweel innovation is its simple
looking hub and spoke design that
replaces the need for air pressure while
delivering performance previously only
available from pneumatic tyres.
Tweel still delivers pneumatic –like
performance weight-carrying capacity, rde
comfort, and the ability to “envelope” road
hazards.
Tread :- The rubber layer that wrap around the
circumference and touches the pavement.
Flexible spokes :- Made up of polyurethane
material with are flexible, help to absorb road
impacts.
Sheer band :- Which surrounding the spoke
Deformable wheel :- Which is in between spokes
and hub, which deforms together with flexible
spokes during road impacts. It is also called as
ENERGY WHEEL.
Hub :- A rigid attachment point to the axle.
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The injection molded polyurethane spoke are flexible; this allows effectively absorb impacts.
The key advance that this system offers a tube of air is that it separates several important ride characteristics.
Lateral stiffness improves cornering; the only way to get that with a traditional tyre is to increase tyre pressure.
The Tweel can be engineered to give five times the lateral stiffness as a pneumatic tyrewithout any loss in ride comfort.
How does it works?.
Flexible spokes are fused
with a flexible wheel which
deforms to absorb shock.
The Tweel also has a unique
capability to have different
vertical and lateral stiffness.
The vertical stiffness affects
ride comfort, and lateral
stiffness affects handling and
cornering.
The best of both worlds, ride
comfort and superb handling!
On working the Tweel is a single unit, though it
actually begins an assembly of four pieces
bonded together: the hub, polyurethane spoke
section, a “sheer band” surrounding the spoke
and the tread band.
The sheer band surrounding the spokes
effectively takes the place of air pressure,
distributing the load.
The tread is similar in appearance to a
conventional tyre.
Tweel works well over rocky terrains, so it
should work well for four-wheel vehicles too.
The tension of the sheer
band on the spokes and the
strength of spokes
themselves replace the air
pressure of a traditional tyre.
The tread is then attached to
the sheer band.
The Tweel looks sort of like a
very large, futuristic bicycle
wheel.
When the Tweel put to the
road, the spokes absorb
road impact the same way
air pressure does in
pneumatic tyres.
The tread and sheer bands
deform temporarily as the
spokes bend, then quickly
spring back into shape.
Advantages of Tweel
MAIN ADVANTAGES
The tyres require less maintenance. The materials used in the tyres and spokes are 100% recyclable.
Provides low rolling resistance and contributing to reduction CO2 emissions.
Nothing to do with fuel efficiency in a direct way, only offering the benefit that it will never influence consumption.
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.1. Increased versatility:
Using high- strength but
flexible high- performance
resin as a material has
increased versatility through
improved load- bearing
capabilities and driving
performance.
High speed travel
(maximum 60 km/h) in ultra
light vehicles has also
become possible.
2. Low rolling resistance :
About 90% of energy losses from tyre rolling
resistance comes from repeated changes in the
shape of tyres as they roll.
Bridgestone was succeeded in making a
significant reduction in energy losses by using
proprietary material technologies and
simplifying the structure of the tyres.
As a result, these “Air Free Concept Tyre” have
achieved the same level of low rolling
resistance as our pneumatic fuel- efficient
tyres, making possible a contribution to
reduction in CO2 emissions.
3. No Maintenance:-
o Tweel is one single unit replacing the current
tyre/wheel/valve assembly.
o There is no need for complex wheel/tyre
mounting equipment.
o Once they are bolted on, there is no air pressure
to maintain
4. No Compromise with Conventional Tyre :-
Productivity can be increased be because the
Tweel provides greater stability and enables a skid
steer to work faster with more comfort for the
operator, reducing driver fatigue while improving
productivity.
The Tweel delivers a consistent footprint with
strong wear life that is two to three times that of the
pneumatic tyre at equal tread depth.
Additionally, the unique energy transfer within the
poly-resin spokes reduces the “bounce” associated
with pneumatic tyres.
5. No Downtime :-
• Tweel performs like a
pneumatic tyre but without
the risk and costly down
time associated with
penetrations and impact
damage.
Disadvantages of Tweel1. Lack of adjustability :-
One of the biggest disadvantages of the Tweel
is that once manufactured, it cannot be
adjusted.
In this case if car needed a different kind of
setting, a whole new set of Tweel will be
required.
2. Not economic as Pneumatic Tyres :-
Vehicles are currently working on enabling the
Tweel to be as fuel efficient as pneumatic tyres.
Currently they are within 5% of the rolling
resistance and mass levels.
3. Vibration :-
This is the one of the Tweels biggest downsides.
Vibrations becomes considerate once a vehicle
is driving above 50 mph, while
causing a lot of noise.
Also disturbing is the amount of heat the Tweels
generate.
Long distance journey with tweel would be very
un pleasant unless these areas are improved
upon.
Future challenges :
Goodyear in collaboration with NASA Glen
Research Center (GRC), develop non-pneumatic
tyres for use first on Moon, and eventually on
Mars.
“The basic rubber pneumatic design used on
Earth does not have the same utility on Moon” –
NASA Principle Investigator Vivake Asnani.
There is no Lunar roads, Lunar tyres need to be
designed to develop traction on sandy undulated
terrain, in regions that humans have never been
seen up close
The spring tyre has now been recognized with a so called “Oscar Of Innovation” at 44th
Annual R&D 100 Awards in Orland, Florida.