Pneumatic tires

Commencing in the late 1930s, new developments to make very strong yams allowed the viscose rayon to replace cotton as the fiber of choice for longer life pneumatic tires. The pace of this line of development increased during World War II, and by the 1960s a significant part of the production of viscose yam was for tires and industrial appHcations. 

Composites. Various composite materials have evolved over the years as a significant class of high performance textile products. The prototype composite is carbon fiber with an epoxy resin matrix for stmctural akcraft components and other aerospace and military appHcations. Carbon fiber composites ate also used in various leisure and spotting items such as golf clubs, tennis rackets, and lightweight bicycle frames. However, other types of appHcations and composites ate also entering the marketplace. For example, short ceUulose fiber/mbbet composites ate used for hoses, belting, and pneumatic tire components. 

The basis for reinforcement of a pneumatic tire requires placing the strength or tensile member in a preferred direction, depending on the location and cord function in the tire. An overview of the tire production process, including essential elements of transforming a continuous yam into a usehil embodiment for tire reinforcement, is shown in Figure 2. 

The basic principles and approaches to manufacturing pneumatic tires have been in place for many years, and because of the scale of modem tire production, radical change is slow. However, developments of new tire production processes continue (44,45) and as new methods take hold, it is likely that changes in tire cord handling and preparation will be required. 

Standard Test Methods for Steel Tire Cord. ASTM standard D2969-92 includes test methods for steel cords that are specifically designed for use in the reinforcement of pneumatic tires. It describes test methods determining steel cord constmction, break strength, elongation at break. 

Standard Test Methods for Tire Yarns, Cords, and Woven Fabrics. ASTM standard D885M-94 includes test methods for characterizing tire cord twist, break strength, elongation at break, modulus, tenacity, work-to-break, toughness, stiffness, growth, and dip pickup for industrial filament yams made from organic base fibers, cords twisted from such yams, and fabrics woven from these cords that are produced specifically for use in the manufacture of pneumatic tires. These test methods apply to nylon, polyester, rayon, and aramid yams, tire cords, and woven fabrics. 

Scottish inventor ]chn Boyd Dunlop, displays an invention he patented in 1888—the bicycle with pneumatic tires. (Corbis-Betlmann)... 

The first commercially successful pneumatic tire was developed in 1888 in Belfast by the Scottish veterinarian John Boyd Dunlop primarily to improve the riding comfort of bicycles. Dunlop also showed, albeit qualitatively, that his air-inflated pneumatic took less effort to rotate than did the solid rubber tires in use at that time. His qualitative tests were the first known rolling resistance experiments on pneumatic tires. Due to this significant reduction in rolling loss, many professional cyclists in Britain and Ireland adopted air-inflated tires for their bicycles by the early 1890s. Pneumatics for the nascent automobile industry soon followed. 

The pneumatic tire has the geometry of a thin-wallcd toroidal shell. It consists of as many as fifty different materials, including natural rubber and a variety ot synthetic elastomers, plus carbon black of various types, tire cord, bead wire, and many chemical compounding ingredients, such as sulfur and zinc oxide. These constituent materials are combined in different proportions to form the key components of the composite tire structure. The compliant tread of a passenger car tire, for example, provides road grip the sidewall protects the internal cords from curb abrasion in turn, the cords, prestressed by inflation pressure, reinforce the rubber matrix and carry the majority of applied loads finally, the two circumferential bundles of bead wire anchor the pressnrized torus securely to the rim of the wheel. 

Schuring, D. J. (1980). The Rolling Loss of Pneumatic Tires. Ruhher Clhcmistiy and Technology. 83 600-727. Tabor, D. (1994). The Rolling and Skidding of Automobile Tyres. Physics Education 29 301-306. 

Generally speaking, commercial rubber products are manufactured as a composite from a rubber and a nano-filler, which is in a group of fillers of nanometer size (mainly, carbon black and particulate silica). For an example, a pneumatic tire for heavy-duty usages such as aircrafts and heavyweight tracks is made from natural rubber (NR) and carbon black and/or silica. Their reinforcing ability onto rubbers makes them an indispensable component in the rubber products [1,2]. 

FIGURE 26.25 Diagrammatic view of the combined side and braking/accelerating force function for the bmsh wheel model. (From Schallamach, A. and Grosch, K.A., Mechanics of Pneumatic Tires, S.K. Clark (ed.), The US Department of Transportation, National Highway Safety Administration, Washington DV, p. 419.)... 

This chapter is based on two chapters, which the author wrote for The Pneumatic Tire edited by professor A.N. Gent and professor J. Walters of the University of Akron and published by the National Highway Safety Administration of the U.S. Government who all gave their kind permission to use these two chapters when compiling this one. I am very grateful for this. 

The heart of tweel innovation is its deceptively simple looking hub and spoke design that replaces the need for air pressure while delivering performance previously only available from pneumatic tire. The flexible spokes are fused with a flexible wheel that deforms to absorb shock and rebound with unimaginable ease. Without the air needed by conventional tires, tweel still delivers... 

The pneumatic tire, which already performs remarkable functions at a very modest cost, will continue to develop and further enhance its values to the customer. 

The rubber stock, once compounded and mixed, must be molded or transformed into the form of one of the final parts of the tire. This consists of several parallel processes by which the sheeted rubber and other raw materials, such as cord and fabric, are made into the following basic tire components tire beads, tire treads, tire cords, and the tire belts (fabric). Tire beads are coated wires inserted in the pneumatic tire at the point where the tire meets the wheel rim (on which it is mounted) they ensure a seal between the rim and the tire. The tire treads are the part of the tire that meets the road surface their design and composition depend on the use of the tire. Tire cords are woven synthetic fabrics (rayon, nylon, polyester) impregnated with rubber they are the body of the tire and supply it with most of its strength. Tire belts stabilize the tires and prevent the lateral scrubbing or wiping action that causes tread wear. 

Rubber gained worldwide importance with the invention of the air-filled or pneumatic tires by a Scotsman, John Dunlop, in 1888. He had a successful veterinarian practice in Belfast. In his off time he worked to improve the ride of his son s tricycle. His invention happened at the right time. The automobile was emerging and the air-filled tires offered a gentler ride. Thus was begun the tire industry. 

The pneumatic tire consists of two basic areas the tread area which is responsible for ground contact, and the casing which is responsible for supporting load and transmitting power to the tread area. Each of these areas has several components with markedly divergent properties which serve specific and unique functions, and all of which must interact with integrity for maximum performance. 

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