Alberto Kazushi Nagaoka

Avaliação do contato pneu-solo em três modelos de pneus agrícolas

The aim of this study was to evaluate the tire/ground contact areas, tire elastic deformation, cone index and foot printed on the ground of tire models. The experiment was done in 12 treatments and four repetitions with three tire models: bias ply, radial and bias belt. The tires were inflated with right inflation pressures and four radial loads were applied on the wheels: 5; 10; 15 and 20 kN, simulating what happens in the field. The agricultural tire tests were carried out at Sao Paulo State University, Botucatu - SP, Brazil, using a hydraulic press over the soil bin. The contact area and elastic deformation results showed highest values for bias belt tire. The soil sinkage of bias belt tire was smaller than other pneumatic tires. The radial and bias belt tires exercised smaller cone index than bias ply tire.

Consumo de combustível de um trator em função do tipo de pneu, da lastragem e da velocidade de trabalho

The objective of this study was to compare the consumption of fuel of the FWD agricultural tractor, equipped with three types of tyres (bias ply, radial and low pressure), with and without tyre water ballasting, operating in four forward speeds. The research was carried out at FCAV/UNESP, SP, Brazil, The soil was tilled using a chisel plow. A tractor with 89 kW (121 HP) engine power equipped with FWD was used in the experiment, and the tyres used had the following characteristics: radial (front: 14.9R26 and rear: 620/75R30), bias ply (front: 14.9-26 and rear: 23.1-30) and low pressure (front: 500/60-26.5 and rear: 700/55-34). The experiment was conducted in a completely randomized block design (3x2x4), with a total of 24 treatments and three replications. The results evidenced advantages for the tractor equipped with radial tyres. The ballasting condition with water in the tyres showed lower specific consumption. It was also observed that the increase of the forward speed reduced the specific consumption.

Desempenho de um trator em função do tipo de pneu, da lastragem e da velocidade de trabalho

The objective of this study was to compare the performance of the FWD agricultural tractor, equipped with three types of tires (bias ply, radial and low pressure), with and without tire water ballasting, operating in four forward speed. The research was carried out at UNESP, SP, Brazil, with the tractor pulling a chisel plow. A tractor with 89kW (121cv) engine power equipped with FWD, was used in the experiment, and the tires used had the following characteristics: radial (front: 14.9R26 and rear: 620/75R30), bias ply (front: 14.9-26 and rear: 23.1-30) and low pressure (front: 500/60-26.5 and rear: 700/55-34). The experiment was conducted in a completely randomized block, design (3x2x4), with 24 treatments and three replications. The results evidenced advantages for the tractor equipped with radial tires.

Evaluation of a Single Wheel Testing Device with Mechanical Transmission

Single Wheel Testing Device was projected, built, instrumented, and evaluated using a mechanical transmission of a tractor, linked to a power take off of an auxiliary tractor. The device was mounted using half of a standard tractor differential and transmission gear totalizing 24 forward speed options. The Device was equipped with several sensors (torque, rotation, force, fuel consumption) hooked up to a data logger, permitting to determine wheel performance parameters, net and gross traction coefficient, and tractive efficiency. Tests were realized in different soil surfaces and tire conditions, varying the forward speed and slip up to 14 km/h and 34%, respectively, The results of a comparative research using radial and bias ply tires under different tire pressures and loads showed the best performance for radial ply tires.

Soil Physical Parameters Related with Agricultural Machine Workdays

The modern agricultural technology is based on intensive machine use that promote strong alterations on soil physical parameter, such as, soil density, porosity and compaction. This alterations contribute to decrease crop yield and minimize farmer savings. This research was conducted with the aim to develop and evaluate a methodology to determine soil physical parameters related to agricultural machine workdays. A computational system was developed to determine dynamical soil/wheel contact pressure and the soil load capacity, based on preconsolidation pressure. To evaluate this methodology, a experimental design was done in a Latossolo roxo (heavy clay soil), in Botucatu county, Brazil, constituted by two traffic conditions (with and without) and four periods after rain (one, two, four and six days), followed an random blocks design with sub-parcels. There was no statistical difference on soil density before traffic showing that the compaction was uniformly distributed all over the parcels. After traffic the density has increased about 24.7%, 19.3%, and 14.6% for one, two and four days after rain, respectively. There was no significantly statistical difference on soil density for six days after rain condition, showing that the waiting time after rain to realize traffic with dynamic pressure of 1169 kPa should be between 4 - 6 days.