Krzysztof Pieczarka, Mateusz Kierdal, Krzysztof Lejman and Zygmunt Owsiak
The research concern selected traction properties of Massey Ferguson 7475 wheeled tractor, which were carried out on various deformable surfaces i.e. soil: after ploughing, sodded and with rye fore crop. The impact of driving speed on tractive power and force with 2WD and 4WD drive was investigated. Physical and chemical properties of soil during testing were characterised by moisture, compactness and maximum shearing stresses. Studies on traction properties were carried out with the use of two tractors: Massey Ferguson 7475 and New Holland 5040. During measurements, tractors were connected with a tow rod, where a strain force transducer was mounted. The stand enabled also measurement of theoretical speed. As a result of analyses of the obtained results, characteristics of tractive force and towing power as a function of slip were made. The tests confirmed that the use of four-wheel drive is unjustified because it improves these tractive parameters of a tractor. It was reported that the maximum force and towing power are generated for the lowest values of slip which is equal to 0.1 on the sodded surface. However, value of this power is the lowest in comparison to other surfaces. The highest value of the adhesion coefficient was reported on soil with rye fore crop.
Jarosław Czarnecki, Marek Brennensthul, Włodzimierz Białczyk, Weronika Ptak and Łukasz Gil
The paper presents results of the research on traction properties of two tractor tyres used on two agricultural grounds. The first ground was a stubble and the second one cropland. The investigated tyres had the same structure (diagonal, with a traditional tyre tread but different external dimensions. The research was carried out in field conditions with the use of a stand aggregated with a farm tractor. Analysis covered traction efficiency, slide, towing power and power lost on the rolling resistance and wheel slide. Based on the obtained results it was concluded that on a ground with lower compaction, the values of power losses were higher and traction efficiency was lower. Moreover, it was proved that the value of the power lost for rolling resistance had a decisive impact on the values of traction efficiency