The transmission system of an agricultural tractor has a main purpose to transmit the power generated in the hydraulic motor, the power take off and the drive wheels. The gearshift consists of a series of gears that allows the correct selection of speed and torque more appropriate to a particular operation. Then, the transmissions can be classified, basically, in three categories: mechanical, hydrostatic and hydrodynamic, being the mechanical transmissions subdivided in sliding gear and synchronized. Then, the objective of this research was to analyze the different types of transmissions available in 169 models of tractors made in Brazil in order to evaluate the real distribution of them in different power ranges and establish possible correlations. As a result, it was shown a strong tendency for agricultural tractors with power less than 111.8kW possessing mechanical transmission and tractors above 111.8kW possessing the hydrostatic type.
gearshift; power range; classification
