Análise operacional de um trator agrícola em função da pressão interna dos pneus e inclinação da linha de tração

• Autor(a) principal: Furtado Júnior, Marconi Ribeiro
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3636
• topic: Máquinas agrícolas; Força de tração; Pneus; Vibração; Agricultural machinery; Traction force; Tires; Vibration; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA

The importance of Brazilian agriculture in the global scenario is closely related to the expansion of the agricultural frontier throughout the country in recent decades. This process occurred through the use of new techniques, processes and equipment that allowed the expansion of crops for areas previously considered unsuitable. The tractor had an instrumental role in jump national agriculture and can be considered the main source of power in the field. The use of tractors in production enhances the quality of service performed and ensures achieving greater operational efficiency at all stages of production. The tractor is a complex machine, comprising a number of elements and mechanisms which operate concurrently to ensure basic function of a tractor, in other words, provide power for agriculture. The performance of a machine in traction is affected by several variables such as the internal pressure of the tires and weight transfer. Thus, the aim of this work was to evaluate the following questions: Influence of the internal pressure of the tires and the slope of the line traction in operating parameters and the mechanical vibration of the base station operation; Change in the internal pressure of the tire dynamic condition due to the weight transfer between front and rear axle. Work was done on the campus of the Federal University of Viçosa, in the period from March to August 2012. The experiment conducted to determine the performance and vibration in the post of operation was performed in firm ground track, and the treatments of the combination of three tire inflation pressure (12, 14 and 16 psi), three inclinations of traction line and four traction forces (3.57, 6.86, 12.46 and 16.23 kN), in a completely randomized design, with eight replications. The experiment conducted to evaluate the variation of the internal pressure of the tires in dynamic condition was performed on concrete track, with four treatments consisting of traction forces of 4.44, 14.57, 18.6 and 23.92 kN, in a completely randomized design, with four replications. We used a tractor with front wheel assist, equipped with bias tires and a set of transducers for measuring the parameters of interest. The results showed that the slip of wheelsets of the tractor increased progressively with increasing traction force, that reducing the internal pressure of the tires caused a reduction in the slip of the wheelsets in the greatest traction forces and that the inclination of the line traction had significant effect only for the tensile strength of 16.23 kN. The hourly fuel consumption increased by about 65% with increasing tensile strength of 3.56 to 16.23 kN, the internal pressure of the tires and the class of inclination of the line traction had limited effect on this variable. The traction force and the internal pressure of the tire exerted a positive effect on levels of longitudinal vibration at the base of the post operating, the highest levels were observed for the combination of tensile strength of 16.23 kN and the internal pressure of 110,32 kPa, with values close to 0,61 m s-2, and the lowest for the force of 3,56 kN and 82,74 kPa pressure, with values close to 0,20 m s-2. The traction force and the internal pressure of the tires had a quadratic effect on vibration levels in the vertical direction at the base of the post operating, the highest levels were observed for the combination of traction force of 16,23 kN and the internal pressure of 110,32 kPa, with values close to 0.75 m s-2, and the lowest for the force of 3,56 kN combined with the internal pressure of the tires of 82,74 kPa. The variation of weight transfer acting on each axle of the tractor was able to provide the change in the internal pressure of tires in dynamic condition. The traction force showed a linear variation of the internal pressure of the tire during the development of tensile, being generated model considered valid to estimate the traction force from the variation of the internal pressure of the tires.