Avaliação do desempenho de pneus agrícolas utilizando equipamento de teste de pneus “in situ” (“UCD-Single Wheel Tester”).

Abstract

The main objective of this research was quantifying and evaluating the benefits of employing "low/correct" pressure radial ply tires used in agricultural tractors. The tire model was 710/70R38 used with three inflation pressures: High: 165.5 kPa (24 psi), "low/correct": for rear tires: 49 kPa (7 psi) and "low/correct" for front tires: 42 kPa (6 psi) operating in two soil conditions: Tilled (loose) and No Tilled (firm) and two soil moisture: Wet and Dry. The experiment was ran using a device for individual tire tests (mobile soil bin) named "UCD Single Wheel Tester" belonging to University of California, Davis, USA, varying the slip (S) from zero to 30 %. The following parameters were recorded in each run: Vertical Load (W), Draft (D), Torque (T), tire rotation, carriage forward speed (V) and tire rolling radius (r). The data were transformed using a computer program and the following parameters were computed: Net traction Coefficient (NT = D/W), Gross Traction Coefficient (GT = T/rW) and Tractive Efficiency [TE = NT.(1 - i)/GT]. The result analysis showed a significant influence of tire inflation pressure, with best results for "low/correct" inflation pressure treatments, for all evaluated parameters.