Optimum Designing Of Threshing And Separator Unit For Longitudinal Axial-flow Combine Harvester

Threshing and separator device is the core components of a combine. Its main function is to remove grains from millet sprays and separate grains from the prolepses as many as possible. Threshing and separator device has a direct influence on the threshing performance indicators of un-threshing, entrainment loss and broken grain rate. It determines the work quality and productivity of the machine. This paper combined the project of National Ministry of Science and Technology, namely, the subject of "Vertical Pairs of Axial Rice and Wheat Combine Harvester" and studied the parts of the threshing and separator device, conducted a bench orthogonal test as well as. According to the analysis results of the effects of the parameters on performance of threshing and separator device ascertains the optimal proposal finally and provides a design reference for further development of rice for subsequent pairs of vertical axial flow combines.Through theoretical research and experimental verification, the primary conclusions are drawn as follows.(1)The optimal combination program of threshing device is:â‘ the type of roller is the pole-teethâ‘¡roller speed is 750r/minâ‘¢the width in the middle of the concave is 28mm while fore part and posterior segment both are 14mm. The pattern of roller is the most important fact for the loss rate and broken grain entrainment rate.(2) This experiment studies the effect of the interval on the threshing performance and explains the laws that the best solution for wire-grate concave is sparse in the middle while serried at the forepart and back-end from both the aspect of theory and experiment.(3) As the rotate speed of the roller is 750r/min, the threshing performance is the best. If speed is too high or too low, the loss rate, the broken rate and grain entrainment rate both increase accordingly.(4) The main factor of affecting the distribution of grain along the axial direction is the type of roller model. Experiment proves that when the diameter of rod roller tooth circle is 550mm, at the length 1400mm from the beginning, threshing isolation rate reaches more than98%. Therefore, shorten the length of roller is feasible.(5) The bar-tooth roller used in this experiment is easily wrapped around the grass, increases the loading and power consumption, so it is not suitable for rice harvesting. Spike tooth-cylinder performances indicators are better than rasp-bar tooth and bar-tooth roller.