秸秆圆捆机捆绳机构的参数优化与试验

针对我国中小型圆捆机收获的秸秆捆易于膨胀松散、甚至散捆的问题,设计了一种与钢辊式圆捆机相配套的捆绳机构。在秸秆捆力学特性测定及其膨胀变形影响因素分析的基础上,利用钢辊式圆捆机试验台,选取影响捆绳机构性能的导绳轮半径、链轮中心距圆捆机侧壁的安装距离、以及捆绳在秸秆捆端部缠绕的圈数作为试验因素,以秸秆捆膨胀率和捆绳消耗量为评价指标进行试验研究。结果表明:对秸秆捆膨胀率贡献率依次为安装距离、导绳轮半径、圈数;对捆绳消耗量贡献率依次为导绳轮半径、安装距离、圈数。当试验因素参数组合为圈数2圈、导绳轮半径70 mm、安装距离62 mm时,秸秆捆膨胀率为4.42%,捆绳消耗量为2.93 kg/t。研究结果可为圆捆机捆绳机构的研究和设计提供理论及技术依据。

Parameter optimization and experiment of rope-winding mechanism of straw round balers

Abstract: China is rich in crop straw resources, and annual straw output has reached about 700 million t. Due to fluffy and dispersed properties, baling of straw is very necessary for its further utilization. Because round balers don''t have the knotter of square balers, the structure of round balers is relatively simple, and it is widely used both at home and abroad. Small and medium-sized round balers are widely used in the rural areas in China. At present, there are some problems when the straw bales are harvested by small and medium-sized round balers developed in China, and the unreasonable working way of the rope-winding mechanism is one of main reasons. In view of the straw bales harvested by small and medium round balers, easy to expand and loosen, a rope-winding mechanism was designed for the steel-roller round baler. On the basis of the measurement of mechanical property of straw bale and the analysis of influencing factors of straw bale expansion deformation, main structural parameters of the rope-winding mechanism, including wheel radius, installation distance between sprocket center and wall side of baling room and circle number of rope at the end of straw bale, were decided as experimental factors, and expansion rate of straw bales and consumption of ropes were selected as evaluation indices. Experiments were done by the round baler equipped with the rope-winding mechanism. The rope-winding mechanism was able to work smoothly in the experiment. According to experimental results, there were certain interactions among circle number, wheel radius and installation distance. Variance analysis was carried out respectively on the regression models of 2 evaluation indices by the Design Expert software. Known from the analysis of variance, the P values of 2 response surface models were all less than 0.0001, and the lack-of-fits were all non-significant, which demonstrated the effect of factors was outstanding and the model was appropriate. The coefficient of determination (R2) for the models were 0.96 and 0.98 respectively, which indicated that the proposed model was agreeable with the practical condition, and thus the proposed model could be used to predict the change of expansion rate of straw bales and consumption of ropes. The results showed that the contributing rate of each factor on expansion rate of straw bales was mounting distance, radius of guiding wheel, and circle number respectively; the order of contributing rate for each factor on the consumption of ropes from high to low was radius of guiding wheel, mounting distance, and circle number. When the circle number was 2 circles, wheel radius was 70 mm, and mounting distance was 62 mm, the optimal evaluation indices were achieved as follows: expansion rate of straw bale was 4.42%, and consumption of rope was 2.93 kg/t. The experimental results can provide a reference for the design and development of rope-winding mechanism of round balers.