Análise de vibração das hastes de uma colhedora de café

Abstract

Coffee culture is highlighted worldwide by its socioeconomic importance, acting directly or indirectly on many sectors. For the coffee producer to meet the demand and maintain competitive in the market, it is necessary to reduce production costs, which lead to the use of mechanizations in coffee culture, as is the case with coffee (Coffea arabica L.) harvesting, which is an onerous process and demands an elevated cost with labor, which is ever scarcer. The migration of manual harvesting to the semi-mechanized or super-mechanized harvests caused the emergence of new technologies and many models of harvesters. These harvesters present adjustments, which directly influence the efficiency of harvest. However, to understand the dynamic behavior of the components and systems of the harvesters, adjustment and operating recommendations are of extreme importance for the development of new products. In this context, this work was conducted with the objective of evaluating the vibration of the harvesters rods of an automotive coffee harvester in order to know the dynamic behavior in terms of vibration amplitude and frequency and the effect over harvesting. The trials were conducted in the Agriculture Machinery and Mechanization Sector of the Department of Engineering at the Universidade Federal de Lavras – UFLA, in the municipality of Lavras, MG, Brazil. The methodology used employed the concepts of signal processing to reach the results, which were divided into qualitative and quantitative. In the trials, the completely randomized design was used, with subdivided plots, totalizing 81 treatments. The results showed that it was possible to uncover the trajectory performed by the harvesters rods, and that the studies harvester presented higher vibration amplitudes of the rods in the vertical direction when regulated in 8 to 10 Kgf on the break that corresponds, respectively, to the torques of 42.89 and 53.61 N.m, in the vibration of 950 cycles.min-1 of the cylinder and with stems of 570 mm in length. They also showed that the higher efficiency of the combing occurs when therods vibrate in the vertical direction, favoring the higher contact between the stems and the plagiotropic branches and fruits of the coffee plant. The results aid in recommending the adjustment of harvesters and serve as basis for researches and development of new technologies that aim at benefiting the coffee producer.