Active Vocabulary to Text В

NOTES

OF MODERN TRACTORS

CONSTRUCTIONAL FEATURES

TEXT B

Farmers are the principal users of tractors. That is why tractor development is closely¹ connected with agricultural operations. Engineers and designers constantly have to improve the models of tractors. Agriculture needs powerful machines that can provide efficient performance, easy operation, total quality and reliability and long service. Modern tractors are to be constructed with certain features. The basic parts of a tractor are the frame, the traction mechanism, the efficient power unit, the transmission power system, the steering unit, and the working and auxiliary devices.

The frame carries numerous parts that form the tractor. The frame must be rigid² to fix all the units on their places. To prevent tractor parts from damage three-point suspension is commonly used. Two points of the suspension are attached to the rear axle and one point is fitted to the middle of the front axle.

The traction mechanism of a tractor may be of two types: pneumatic wheels or tracks. Tracks are more reliable on heavy, sandy or hilly lands where wheels don't provide perfect adhesion with the soil.

The power unit includes a powerful diesel or petrol engine in which fuel is converted into mechanical energy. Unlike³ a car engine tractor engine is low-speed. The engine may be air-cooled or water-cooled, the latter⁴ being more popular. To lubricate the engine, the force feed method is used.

The transmission system consists of a clutch, mechanically operated gear mechanism, shafts, axles, differential and drives. The function of this system is to transmit the power produced by the engine to the driving speeds of the tractor, operating in different conditions. The transmission system should be compact and reliable.

The steering unit causes the tractor to move, change speed and direction. The working equipment consists of a PTO-shaft, a pulley, a hydraulic system to mount mechanisms, a three-point linkage to control implements. The auxiliary⁵ equipment includes a cab and an operator's seat, heating system; light and sound control devices, etc. One has to know all parts of a tractor and keep them in order to use it with the highest efficiency.

¹closely - тесно

²rigid - жесткий

³unlike - в отличие от

⁴latter - последний

⁵auxiliary - вспомогательный

improve - улучшать	clutch - муфта
frame - рамка	dual clutch-двойная муфта
cause - вызывать	form - образовывать
pulley - ременной шкив	reliable - надежный
fix - укреплять	control - управлять
fixed - неподвижный	numerous - многочисленный
keep - содержать	traction mechanism - ходовая часть
suspension - подвеска	steering - рулевое управление
fit - крепить	force feed method – метод принудительной смазки
order - порядок	perfect - cовершенный, полный

Дата добавления: 2014-10-17