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V Belts and Fan Belts

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					V. Belts and Fan Belts
Introduction
        As the name implies, these power transmission belts have the V-belt cross section.
They have various advantages over flat belts e.g. compactners, quite operation, non slipping
grip between belts and sleeve, absorption of shocks grip between belts and sleeve, absorption
of shocks, smooth starting cleanliness, long service life, low cost and light bearing loads. The
internal structure of standard V-belts varies. Cords are the “back bone― of V-belts.
They are located in the upper wide portion. These cords in the best belts are impregnated and
embedded in a rubber compound which reduces friction between individual strands or fibres
and retards heat build up. This is known as cushion rubber. This is embedded in a mass of
solid rubber; it is known as core. Core is the belt that improves flexibility and increase shock
absorption.

        In starting, monetary stresses greater than those encountered in running must be
withstand, and this core rubber acts as an absorber for the sudden pull, thus protecting the
cords and cover. When the belt travels around a sleeve. The narrower a portion is
compressed, and the solid rubber must withstand such distortion without accumulating
excessive heat. Special cool running compounds have been developed. The whole thing is
enclosed in rubber fabric jacket or cover which acts as an envelope to resist wear and protects
the inner structure.

        V-belts are specially useful for silent drive between short centre distances and are
used for fractional horsepower drives for domestic appliances and for automatic fan belts.
They come in five standard sizes A, B, C, D, E. The top width of A is 12.7 mm (1/2 in) and
that of E is mm (1) and the thickness varies between the different sizes. When power
transmitted is heavy multiple belts are used in pullies having a number of grooves as
required. More recently, premium industrial belts known as 3V, 5V and 8V belts or wedge
type belts have been introduced. In these the ratio of depth to the top width is greater than in
the standard sections, giving a more compact drive. These constructions are made possible by
the use of high tenacity materials such as polyester cord.

Market Potential
        The demand for fan & V-belts has been estimated by the development penal at around
47.61 million number. It will thus be seen that there is adequate scope for the development of
this item both in the small scale as well as in the organised sector.

        However, as per the recent trends there is a change over for the use of more
sophisticated type of drives such as narrow width belts, raw egged belts, raw egged cogged
belts, space saver belts, timing belts etc.

        Some of the organised units are taking effective steps to undertake the manufacture of
these types of sophisticated belt in the country.

By and large, plant & Machines for the manufacture of fan & V-belts are available
indigenously for undertaking new types of belts are required to be imported. Similarly
technical know-how for the conventional fan & V-belts is also available. However, foreign
collaboration for new types of belts are considered on merits. Major raw materials are also
available indigenously.

				
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posted:8/19/2010
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Chandra Sekhar Chandra Sekhar http://
About My name is chandra sekhar, working as professor