STREAM SEMINAR VISHAL CHATURANI B. TECH (MECHANICAL) 114089 Dayalbagh Educational Institute

Automobile Tyres

INTRODUCTION Tyre is a rubber member which gives the cushion to the automobile. It consists of outer cover i.e. tyre proper and tube inside. The tyre-tube assembly is mounted over the wheel rim and air inside the tube carries entire load and provides cushion.

Functions of tyre To support the vehicle load. To provide cushion against the shocks. To transmit driving and braking forces to the road. To provide cornering power for smooth steering.

Properties of tyres Non-skidding Uniform wear Load-carrying Cushioning Power consumption Tyre noise Balancing

Types of tyres Conventional tubed tyre. Tubeless tyre.

Advantages of tubeless tyres Lesser unsprung weight. Better cooling. Lesser rolling resistance. Comfortable ride. Slower leakage of air. Simpler assembly. Improved safety.

NON PNEUMATIC TYRES Bridgestone Corporation announced it has developed “Air Free Concept (Non-Pneumatic) Tire” at the 43 Tokyo Motor Show 2013. The airless tire is not a new concept and is under investigation by several tire manufacturers since a while

INTRODUCTION Since the earlier invention of a non-pneumatic wheel in 1920’s, the non-pneumatic tire (NPT) is getting more attention due to its advantages over the pneumatic counterpart. Many design studies are still needed from the viewpoint of material, pattern, and structures. However, no systematic research for such important design issues has been reported in the literature up to now.

The airless tire is not a new idea – “MichelinTweel” is just another example - but Bridgestone claims that this is the first design of its kind that is ready for mass production.

What makes tyres “AIR LESS” Structure of spokes stretching along the inner sides of the tires supporting the weight of the vehicle. A synthetic resin that becomes flexible when heated, can be processed into a variety of shapes, and becomes hard when cooled. The changes from heating and cooling can generally be repeated, making it easy to both mold and recycle the material.Untitled.mp4 Tubeless tire technology does away with the need for an inner tube thereby increasing safety.[citation needed] In a tubeless tire, the tire and the rim of the wheel form an airtight seal, with the valve being directly mounted on the rim. If a tubeless tire gets a small puncture, air escapes only through the hole, leading to a gentle deflation. Conversely, an inner tube could potentially burst like a balloon, leading to a rapid deflation of the tire which could result in sudden loss of control of the vehicle.

Flexing of spokes

ADVANTAGES The tires require less maintenance  The worry of punctures is eliminated. The materials used in the tires and the spoke structure are 100% recyclable.  Provides low rolling resistance and contributing to reductions in co2 emissions. Nothing to do with fuel efficiency in a direct way, only offering the benefit that it will never influence consumption. no need to periodically refill the tires with air

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 ultralight vehicles has also become possible.  “cradle to cradle” process that maximizes the cyclical use of resources from worn tires into new tires and the use of recyclable resources.

Low rolling resistance About 90% of energy loss from tire rolling resistance comes from repeated changes in the shape of tires as they roll. Bridgestone has succeeded in making a significant reduction in energy loss by using proprietary materials technologies and simplifying the structure of the tires. As a result, these “Air Free Concept tire” have achieved the same level of low rolling resistance as our pneumatic fuel-efficient tires, making possible a contribution to reductions in CO2 emissions. NOTE: 1. Still in the testing phase 2. There is no word on price or a release date for standard vehicle versions.

TWEEL by Michelin Tweel for Segway. Tweel for construction vehicle

3D model of airless tire

Michelin first announced the Tweel in 2005 The name is a combination of the words tire and wheel because the Tweel doesn’t use a traditional wheel hub assembly.   A solid inner hub mounts to the axle. That’s surrounded by polyurethane spokes arrayed in a pattern of wedges. A shear band is stretched across the spokes, forming the outer edge of the tire (the part that comes in contact with the road).

The tension of the shear band on the spokes and the strength of the spokes themselves replace the air pressure of a traditional tire. The tread is then attached to the shear band. The Tweel looks sort of like a very large, futuristic bicycle wheel.

When the Tweel is put to the road, the spokes absorb road impacts the same way air pressure does in pneumatic tires. The tread and shear bands deform temporarily as the spokes bend, then quickly spring back into shape.

Bridgestone vs Michelin Bridgestone’s prototype version looks very similar to that of Michelin. In Michelin’s design the thermoplastic fins are staggered so that the connections to the hub and the rim won’t torque causing complete structural breakdown.

The biggest difference between the two tire maker’s wheels, as pictured above, is the size of the supporting ribs. Michelin focused on allowing the tires to be able to deform over obstacles, making them more suitable for military applications where as Bridgestone has approached its tire from the consumer angle, creating a highly recyclable tire that will cut down on maintenance costs and time

FUTURE CHALLENGES Goodyear in collaboration with NASA Glenn Research Center (GRC), develop non-pneumatic tyres for use first on the moon, and eventually on Mars. the innovator of innovative tyre technology on Earth

“The basic rubber-pneumatic design used on Earth does not have the same utility on the moon,” said NASA Principal Investigator Vivake Asnani. There are no lunar roads. Lunar tyres need to be designed to develop traction on sandy undulated terrain, in regions that humans have never even seen up close.

The Spring Tire has now been recognized with a so-called “Oscar of Innovation” at the 44th Annual R&D 100 Awards in Orlando, Florida.

REFERENCES www.google.com http://www.bridgestone.co.in/ http://www.newindianexpress.com/business/news/article284682.ece http://gizmodo.com/tag/tires http://www.toxel.com/tech/2009/07/05/innovative-airless-tires-by-michelin/.

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