脱粒滚筒结构形式对大豆机收质量影响的试验研究.

Grain threshing and separation are the main stages that cause grain breakage in the process of mechanized soybean harvesting. The harvest quality of soybean depends mainly on the configuration of threshing parts, particularly on the structural and performance parameters. In this study, a feasible threshing drum with replaceable components was proposed to investigate the influence of various factors in the mechanical process on the harvest quality of soybean. Lindou 11 was selected as the test material with a moisture content ranging from 10.1% -20.2% in the Linyi area. The impact of soybean machine harvest quality provided in-kind support. The arch teeth, ribs, and rod teeth were selected as the typical threshing components. The threshing drum with replaceable components was characterized by a unique drum spindle assembled by the replacing threshing bar unit and the adding fixed plate, as well as the drum shell in turn. Three types were obtained, including the rod-tooth, combined pattern rod/rod-tooth, and closed bow-tooth threshing drum. Experimental factors were selected as the forward speed, cylinder speed, threshing clearance, and angle of the guide plate. The evaluation indices of soybean were set as the seed crushing rate and un-depurated rate, according to the characteristics of soybean plants. A single factor test was designed to obtain the optimal working parameters of each influencing factor. Four factors were gained for the best drum structure and the optimal combination of operating parameters. A three-level orthogonal test was conducted to determine the significance of the influence of each influencing factor on the evaluation index. An evaluation test was designed to verify the accuracy of obtained data from the field test. The test results show that the forward speed and cylinder speed had a greater influence on the crushing rate, whereas, the cylinder speed and threshing clearance had a greater influence on the un-depurated rate. There was generally high threshing quality in the combined rod/rod-tooth threshing drum when the moisture content of soybean was in the range of 10.1%-15.4%.The influencing factors on the grain crushing rate were ranked in a descending order: the cylinder speed, forward speed, threshing clearance, and guide plate angle. The primary and secondary orders on the un-depurated rate were the cylinder speed, threshing clearance, guide plate angle, and forward speed. The threshing quality in the closed bow-tooth threshing drum was relatively high in the range of 17.8%-20.2% moisture content. The influencing factors on the grain crushing rate were as follows, the cylinder speed, forward speed, guide plate angle, and threshing clearance, where those on the un-depurated rate were in the order of threshing clearance, cylinder speed, guide plate angle, and forward speed. When the moisture content of soybean was in the range of 10.1% -15.4%, the combined bar-rod-tooth threshing drum was at a forward speed of 4km/h, a cylinder speed of 600r/min, a threshing clearance of 30mm, and a guide plate angle of 70°, where the crushing rate and un-depurated rate were the lowest, 0.90% and 0.18%, respectively. When the moisture content was in the range of 17.8%-20.2%, the closed bow-tooth threshing drum had a forward speed of 3km/h, the cylinder speed of600r/min, the threshing clearance of25mm, and the guide plate angleof75°, where the crushing rate and un-depurated rate were the lowest, 1.2% and 0.23% respectively, indicating an excellent harvest quality. The findings can provide a potential reference to design the promising threshing drum in a grain harvester. [ABSTRACT FROM AUTHOR]